Windows sockets error codes - Исправление ошибок и поиск оптимальных решений проблем

THE INFORMATION IN THIS ARTICLE APPLIES TO:

All Windows-based products

DISCUSSION

The table below lists some common Winsock error codes. Also refer to the Microsoft MSDN Library article «Winsock Error Codes» at http://msdn.microsoft.com/en-us/library/aa924071.aspx.

Return Code	Value	Description
WSAEINTR	10004	Interrupted function call. A blocking operation was interrupted by a call to WSACancelBlockingCall.
WSAEACCES	10013	Permission denied. An attempt was made to access a socket in a way forbidden by its access permissions. An example is using a broadcast address for sendto without broadcast permission being set using setsockopt(SO_BROADCAST). Another possible reason for the WSAEACCES error is that when the bind function is called (on Windows NT 4 SP4 or later), another application, service, or kernel mode driver is bound to the same address with exclusive access. Such exclusive access is a new feature of Windows NT 4 SP4 and later, and is implemented by using the SO_EXCLUSIVEADDRUSE option.
WSAEFAULT	10014	Bad address. The system detected an invalid pointer address in attempting to use a pointer argument of a call. This error occurs if an application passes an invalid pointer value, or if the length of the buffer is too small. For instance, if the length of an argument, which is a sockaddr structure, is smaller than the sizeof(sockaddr).
WSAEINVAL	10022	Invalid argument. Some invalid argument was supplied (for example, specifying an invalid level to the setsockopt function). In some instances, it also refers to the current state of the socket—for instance, calling accept on a socket that is not listening.
WSAEMFILE	10024	Too many open files. Too many open sockets. Each implementation may have a maximum number of socket handles available, either globally, per process, or per thread.
WSAEWOULDBLOCK	10035	Resource temporarily unavailable. This error is returned from operations on non-blocking sockets that cannot be completed immediately, for example recv when no data is queued to be read from the socket. It is a nonfatal error, and the operation should be retried later. It is normal for WSAEWOULDBLOCK to be reported as the result from calling connect on a non-blocking SOCK_STREAM socket, since some time must elapse for the connection to be established.
WSAEINPROGRESS	10036	Operation now in progress. A blocking operation is currently executing. Windows Sockets only allows a single blocking operation—per- task or thread—to be outstanding, and if any other function call is made (whether or not it references that or any other socket) the function fails with the WSAEINPROGRESS error.
WSAEALREADY	10037	Operation already in progress. An operation was attempted on a non-blocking socket with an operation already in progress—that is, calling connect a second time on a non-blocking socket that is already connecting, or canceling an asynchronous request (WSAAsyncGetXbyY) that has already been canceled or completed.
WSAENOTSOCK	10038	Socket operation on nonsocket. An operation was attempted on something that is not a socket. Either the socket handle parameter did not reference a valid socket, or for select, a member of an fd_set was not valid.
WSAEDESTADDRREQ	10039	Destination address required. A required address was omitted from an operation on a socket. For example, this error is returned if sendto is called with the remote address of ADDR_ANY.
WSAEMSGSIZE	10040	Message too long. A message sent on a datagram socket was larger than the internal message buffer or some other network limit, or the buffer used to receive a datagram was smaller than the datagram itself.
WSAEPROTOTYPE	10041	Protocol wrong type for socket. A protocol was specified in the socket function call that does not support the semantics of the socket type requested. For example, the ARPA Internet UDP protocol cannot be specified with a socket type of SOCK_STREAM.
WSAENOPROTOOPT	10042	Bad protocol option. An unknown, invalid or unsupported option or level was specified in a getsockopt or setsockopt call.
WSAEPROTONOSUPPORT	10043	Protocol not supported. The requested protocol has not been configured into the system, or no implementation for it exists. For example, a socket call requests a SOCK_DGRAM socket, but specifies a stream protocol.
WSAESOCKTNOSUPPORT	10044	Socket type not supported. The support for the specified socket type does not exist in this address family. For example, the optional type SOCK_RAW might be selected in a socket call, and the implementation does not support SOCK_RAW sockets at all.
WSAEOPNOTSUPP	10045	Operation not supported. The attempted operation is not supported for the type of object referenced. Usually this occurs when a socket descriptor to a socket that cannot support this operation is trying to accept a connection on a datagram socket.
WSAEPFNOSUPPORT	10046	Protocol family not supported. The protocol family has not been configured into the system or no implementation for it exists. This message has a slightly different meaning from WSAEAFNOSUPPORT. However, it is interchangeable in most cases, and all Windows Sockets functions that return one of these messages also specify WSAEAFNOSUPPORT.
WSAEAFNOSUPPORT	10047	Address family not supported by protocol family. An address incompatible with the requested protocol was used. All sockets are created with an associated address family (that is, AF_INET for Internet Protocols) and a generic protocol type (that is, SOCK_STREAM). This error is returned if an incorrect protocol is explicitly requested in the socket call, or if an address of the wrong family is used for a socket, for example, in sendto.
WSAEADDRINUSE	10048	Address already in use. Typically, only one usage of each socket address (protocol/IP address/port) is permitted. This error occurs if an application attempts to bind a socket to an IP address/port that has already been used for an existing socket, or a socket that was not closed properly, or one that is still in the process of closing. For server applications that need to bind multiple sockets to the same port number, consider using setsockopt (SO_REUSEADDR). Client applications usually need not call bind at all— connect chooses an unused port automatically. When bind is called with a wildcard address (involving ADDR_ANY), a WSAEADDRINUSE error could be delayed until the specific address is committed. This could happen with a call to another function later, including connect, listen, WSAConnect, or WSAJoinLeaf.
WSAEADDRNOTAVAIL	10049	Cannot assign requested address. The requested address is not valid in its context. This normally results from an attempt to bind to an address that is not valid for the local computer. This can also result from connect, sendto, WSAConnect, WSAJoinLeaf, or WSASendTo when the remote address or port is not valid for a remote computer (for example, address or port 0).
WSAENETDOWN	10050	Network is down. A socket operation encountered a dead network. This could indicate a serious failure of the network system (that is, the protocol stack that the Windows Sockets DLL runs over), the network interface, or the local network itself.
WSAENETUNREACH	10051	Network is unreachable. A socket operation was attempted to an unreachable network. This usually means the local software knows no route to reach the remote host.
WSAENETRESET	10052	Network dropped connection on reset. The connection has been broken due to keep-alive activity detecting a failure while the operation was in progress. It can also be returned by setsockopt if an attempt is made to set SO_KEEPALIVE on a connection that has already failed.
WSAECONNABORTED	10053	Software caused connection abort. An established connection was aborted by the software in your host computer, possibly due to a data transmission time-out or protocol error.
WSAECONNRESET	10054	Connection reset by peer. An existing connection was forcibly closed by the remote host. This normally results if the peer application on the remote host is suddenly stopped, the host is rebooted, the host or remote network interface is disabled, or the remote host uses a hard close (see setsockopt for more information on the SO_LINGER option on the remote socket). This error may also result if a connection was broken due to keep-alive activity detecting a failure while one or more operations are in progress. Operations that were in progress fail with WSAENETRESET. Subsequent operations fail with WSAECONNRESET. For more information see GlobalSCAPE Knowledge Base Article #10235
WSAENOBUFS	10055	No buffer space available. An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full. This error indicates a shortage of resources on your system. It can occur if you’re trying to run too many applications (of any kind) simultaneously on your machine. If this tends to occur after running certain applications for a while, it might be a symptom of an application that doesn’t return system resources (like memory) properly. It may also indicate you are not closing the applications properly. If it persists, exit Windows or reboot your machine to remedy the problem. Another possible solution is to increase the available virtual memory by increasing the size of the Windows paging file. For more information see GlobalSCAPE Knowledge Base Article #10234
WSAEISCONN	10056	Socket is already connected. A connect request was made on an already-connected socket. Some implementations also return this error if sendto is called on a connected SOCK_DGRAM socket (for SOCK_STREAM sockets, the to parameter in sendto is ignored) although other implementations treat this as a legal occurrence.
WSAENOTCONN	10057	Socket is not connected. A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using sendto) no address was supplied. Any other type of operation might also return this error—for example, setsockopt setting SO_KEEPALIVE if the connection has been reset.
WSAESHUTDOWN	10058	Cannot send after socket shutdown. A request to send or receive data was disallowed because the socket had already been shut down in that direction with a previous shutdown call. By calling shutdown a partial close of a socket is requested, which is a signal that sending or receiving, or both have been discontinued.
WSAETIMEDOUT	10060	Connection timed out. A connection attempt failed because the connected party did not properly respond after a period of time, or the established connection failed because the connected host has failed to respond. For more information see GlobalSCAPE Knowledge Base Article #10384.
WSAECONNREFUSED	10061	Connection refused. No connection could be made because the target computer actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host—that is, one with no server application running. Sometimes a 10061 error is caused by either a firewall or anti-virus software presence on the local computer or network connection. Either one may be blocking the ports needed to make a successful FTP connection to the server. For a regular FTP session, disable the firewall or anti-virus software or configure it to allow CuteFTP to establish an FTP session over ports 20 and 21. Consult the documentation or help file for your specific firewall or antivirus software product for further instructions. Usually, the manufacturer of the device or software has specific instructions available on their website. If you continue to receive the same error after insuring ports 20 and 21 are open, contact the administrator of the server to which you are trying to connect.
WSAEHOSTDOWN	10064	Host is down. A socket operation failed because the destination host is down. A socket operation encountered a dead host. Networking activity on the local host has not been initiated. These conditions are more likely to be indicated by the error WSAETIMEDOUT.
WSAEHOSTUNREACH	10065	No route to host. A socket operation was attempted to an unreachable host. See WSAENETUNREACH.
WSAEPROCLIM	10067	Too many processes. A Windows Sockets implementation may have a limit on the number of applications that can use it simultaneously.WSAStartup may fail with this error if the limit has been reached.
WSASYSNOTREADY	10091	Network subsystem is unavailable. This error is returned by WSAStartup if the Windows Sockets implementation cannot function at this time because the underlying system it uses to provide network services is currently unavailable. Users should check: That the appropriate Windows Sockets DLL file is in the current path. That they are not trying to use more than one Windows Sockets implementation simultaneously. If there is more than one Winsock DLL on your system, be sure the first one in the path is appropriate for the network subsystem currently loaded. The Windows Sockets implementation documentation to be sure all necessary components are currently installed and configured correctly.
WSAVERNOTSUPPORTED	192	Winsock.dll version out of range. The current Windows Sockets implementation does not support the Windows Sockets specification version requested by the application. Check that no old Windows Sockets DLL files are being accessed.
WSANOTINITIALISED	10093	Successful WSAStartup not yet performed. Either the application has not called WSAStartup or WSAStartup failed. The application may be accessing a socket that the current active task does not own (that is, trying to share a socket between tasks), or WSACleanup has been called too many times.
WSAEDISCON	10101	Graceful shutdown in progress. Returned by WSARecv and WSARecvFrom to indicate that the remote party has initiated a graceful shutdown sequence.
WSATYPE_NOT_FOUND	10109	Class type not found. The specified class was not found.
WSAHOST_NOT_FOUND	11001	Host not found. No such host is known. The name is not an official host name or alias, or it cannot be found in the database(s) being queried. This error may also be returned for protocol and service queries, and means that the specified name could not be found in the relevant database.
WSATRY_AGAIN	11002	Nonauthoritative host not found. This is usually a temporary error during host name resolution and means that the local server did not receive a response from an authoritative server. A retry at some time later may be successful.
WSANO_RECOVERY	11003	This is a nonrecoverable error. This indicates that some sort of non-recoverable error occurred during a database lookup. This may be because the database files (for example, BSD-compatible HOSTS, SERVICES, or PROTOCOLS files) could not be found, or a DNS request was returned by the server with a severe error.
WSANO_DATA	11004	Valid name, no data record of requested type. The requested name is valid and was found in the database, but it does not have the correct associated data being resolved for. The usual example for this is a host name-to-address translation attempt (using gethostbyname or WSAAsyncGetHostByName) which uses the DNS (Domain Name Server). An MX record is returned but no A record—indicating the host itself exists, but is not directly reachable.
WSA_INVALID_HANDLE	OS Dependent	Specified event object handle is invalid. An application attempts to use an event object, but the specified handle is not valid.
WSA_INVALID_PARAMETER	OS Dependent	One or more parameters are invalid. An application used a Windows Sockets function which directly maps to a Windows function. The Windows function is indicating a problem with one or more parameters.
WSA_IO_INCOMPLETE	OS Dependent	Overlapped I/O event object not in signaled state. The application has tried to determine the status of an overlapped operation which is not yet completed. Applications that use WSAGetOverlappedResult (with the fWait flag set to FALSE) in a polling mode to determine when an overlapped operation has completed, get this error code until the operation is complete.
WSA_IO_PENDING	OS Dependent	Overlapped operations will complete later. The application has initiated an overlapped operation that cannot be completed immediately. A completion indication will be given later when the operation has been completed.
WSA_NOT_ENOUGH_MEMORY	OS Dependent	Insufficient memory available. An application used a Windows Sockets function that directly maps to a Windows function. The Windows function is indicating a lack of required memory resources.
WSA_OPERATION_ABORTED	OS Dependent	Overlapped operation aborted. An overlapped operation was canceled due to the closure of the socket, or the execution of the SIO_FLUSH command in WSAIoctl.
WSAINVALIDPROCTABLE	OS Dependent	Invalid procedure table from service provider. A service provider returned a bogus procedure table to Ws2_32.dll. (This is usually caused by one or more of the function pointers being null.)
WSAINVALIDPROVIDER	OS Dependent	Invalid service provider version number. A service provider returned a version number other than 2.0.
WSAPROVIDERFAILEDINIT	OS Dependent	Unable to initialize a service provider. Either a service provider’s DLL could not be loaded (LoadLibrary failed) or the provider’s WSPStartup/NSPStartup function failed.
WSASYSCALLFAILURE	OS Dependent	System call failure. Generic error code, returned under various conditions. Returned when a system call that should never fail does fail. For example, if a call to WaitForMultipleEvents fails or one of the registry functions fails trying to manipulate the protocol/namespace catalogs. Returned when a provider does not return SUCCESS and does not provide an extended error code. Can indicate a service provider implementation error.

Источник

Dev Team blog

How Socket Error Codes Depend on Runtime and Operating System

This post is the first part of a blog post series that covers different technical challenges that we had to resolve during the migration of the Rider backend process from Mono to .NET Core. By sharing our experiences, we hope to help out those who are in the same boat.
There’s too much to share in one post, so we will make this into a series of posts. In this series:

How Socket Error Codes Depend on Runtime and Operating System
How Sorting Order Depends on Runtime and Operating System
How ListSeparator Depends on Runtime and Operating System

Let’s dive in!

Sockets and error codes

Rider consists of several processes that send messages to each other via sockets. To ensure the reliability of the whole application, it’s important to properly handle all the socket errors. In our codebase, we had the following code which was adopted from Mono Debugger Libs and helps us communicate with debugger processes:

protected virtual bool ShouldRetryConnection (Exception ex, int attemptNumber)
{
    var sx = ex as SocketException;
    if (sx != null) {
        if (sx.ErrorCode == 10061) //connection refused
            return true;
    }
    return false;
}

In the case of a failed connection because of a “ConnectionRefused” error, we are retrying the connection attempt. It works fine with .NET Framework and Mono. However, once we migrated to .NET Core, this method no longer correctly detects the “connection refused” situation on Linux and macOS. If we open the SocketException documentation, we will learn that this class has three different properties with error codes:

SocketError SocketErrorCode: Gets the error code that is associated with this exception.
int ErrorCode: Gets the error code that is associated with this exception.
int NativeErrorCode: Gets the Win32 error code associated with this exception.

What’s the difference between these properties? Should we expect different values on different runtimes or different operating systems? Which one should we use in production? Why do we have problems with ShouldRetryConnection on .NET Core? Let’s figure it all out!

Digging into the problem

Let’s start with the following program, which prints error code property values for SocketError.ConnectionRefused:

var se = new SocketException((int) SocketError.ConnectionRefused);
Console.WriteLine((int)se.SocketErrorCode);
Console.WriteLine(se.ErrorCode);
Console.WriteLine(se.NativeErrorCode);

If we run it on Windows, we will get the same value on .NET Framework, Mono, and .NET Core:

	SocketErrorCode	ErrorCode	NativeErrorCode
.NET Framework	10061	10061	10061
Mono	10061	10061	10061
.NET Core	10061	10061	10061

10061 corresponds to the code of the connection refused socket error code in Windows (also known as WSAECONNREFUSED).
Now let’s run the same program on Linux:

	SocketErrorCode	ErrorCode	NativeErrorCode
Mono	10061	10061	10061
.NET Core	10061	111	111

As you can see, Mono returns Windows-compatible error codes. The situation with .NET Core is different: it returns a Windows-compatible value for SocketErrorCode (10061) and a Linux-like value for ErrorCode and NativeErrorCode (111).
Finally, let’s check macOS:

	SocketErrorCode	ErrorCode	NativeErrorCode
Mono	10061	10061	10061
.NET Core	10061	61	61

Here, Mono is completely Windows-compatible again, but .NET Core returns 61 for ErrorCode and NativeErrorCode.
In the IBM Knowledge Center, we can find a few more values for the connection refused error code from the Unix world (also known as ECONNREFUSED):

AIX: 79
HP-UX: 239
Solaris: 146

For a better understanding of what’s going on, let’s check out the source code of all the properties.

SocketErrorCode

SocketException.SocketErrorCode returns a value from the SocketError enum. The numerical values of the enum elements are the same on all the runtimes (see its implementation in .NET Framework, .NET Core 3.1.3, and Mono 6.8.0.105):

public enum SocketError
{
    SocketError = -1, // 0xFFFFFFFF
    Success = 0,
    OperationAborted = 995, // 0x000003E3
    IOPending = 997, // 0x000003E5
    Interrupted = 10004, // 0x00002714
    AccessDenied = 10013, // 0x0000271D
    Fault = 10014, // 0x0000271E
    InvalidArgument = 10022, // 0x00002726
    TooManyOpenSockets = 10024, // 0x00002728
    WouldBlock = 10035, // 0x00002733
    InProgress = 10036, // 0x00002734
    AlreadyInProgress = 10037, // 0x00002735
    NotSocket = 10038, // 0x00002736
    DestinationAddressRequired = 10039, // 0x00002737
    MessageSize = 10040, // 0x00002738
    ProtocolType = 10041, // 0x00002739
    ProtocolOption = 10042, // 0x0000273A
    ProtocolNotSupported = 10043, // 0x0000273B
    SocketNotSupported = 10044, // 0x0000273C
    OperationNotSupported = 10045, // 0x0000273D
    ProtocolFamilyNotSupported = 10046, // 0x0000273E
    AddressFamilyNotSupported = 10047, // 0x0000273F
    AddressAlreadyInUse = 10048, // 0x00002740
    AddressNotAvailable = 10049, // 0x00002741
    NetworkDown = 10050, // 0x00002742
    NetworkUnreachable = 10051, // 0x00002743
    NetworkReset = 10052, // 0x00002744
    ConnectionAborted = 10053, // 0x00002745
    ConnectionReset = 10054, // 0x00002746
    NoBufferSpaceAvailable = 10055, // 0x00002747
    IsConnected = 10056, // 0x00002748
    NotConnected = 10057, // 0x00002749
    Shutdown = 10058, // 0x0000274A
    TimedOut = 10060, // 0x0000274C
    ConnectionRefused = 10061, // 0x0000274D
    HostDown = 10064, // 0x00002750
    HostUnreachable = 10065, // 0x00002751
    ProcessLimit = 10067, // 0x00002753
    SystemNotReady = 10091, // 0x0000276B
    VersionNotSupported = 10092, // 0x0000276C
    NotInitialized = 10093, // 0x0000276D
    Disconnecting = 10101, // 0x00002775
    TypeNotFound = 10109, // 0x0000277D
    HostNotFound = 11001, // 0x00002AF9
    TryAgain = 11002, // 0x00002AFA
    NoRecovery = 11003, // 0x00002AFB
    NoData = 11004, // 0x00002AFC
}

These values correspond to the Windows Sockets Error Codes.

NativeErrorCode

In .NET Framework and Mono, SocketErrorCode and NativeErrorCode always have the same values:

public SocketError SocketErrorCode {
    //
    // the base class returns the HResult with this property
    // we need the Win32 Error Code, hence the override.
    //
    get {
        return (SocketError)NativeErrorCode;
    }
}

In .NET Core, the native code is calculated in the constructor (see SocketException.cs#L20):

public SocketException(int errorCode) : this((SocketError)errorCode)
// ...
internal SocketException(SocketError socketError) : base(GetNativeErrorForSocketError(socketError))

The Windows implementation of GetNativeErrorForSocketError is trivial (see SocketException.Windows.cs):

private static int GetNativeErrorForSocketError(SocketError error)
{
    // SocketError values map directly to Win32 error codes
    return (int)error;
}

The Unix implementation is more complicated (see SocketException.Unix.cs):

private static int GetNativeErrorForSocketError(SocketError error)
{
    int nativeErr = (int)error;
    if (error != SocketError.SocketError)
    {
        Interop.Error interopErr;

        // If an interop error was not found, then don't invoke Info().RawErrno as that will fail with assert.
        if (SocketErrorPal.TryGetNativeErrorForSocketError(error, out interopErr))
        {
            nativeErr = interopErr.Info().RawErrno;
        }
    }

    return nativeErr;
}

TryGetNativeErrorForSocketError should convert SocketError to the native Unix error code.
Unfortunately, there exists no unequivocal mapping between Windows and Unix error codes. As such, the .NET team decided to create a Dictionary that maps error codes in the best possible way (see SocketErrorPal.Unix.cs):

private const int NativeErrorToSocketErrorCount = 42;
private const int SocketErrorToNativeErrorCount = 40;

// No Interop.Errors are included for the following SocketErrors, as there's no good mapping:
// - SocketError.NoRecovery
// - SocketError.NotInitialized
// - SocketError.ProcessLimit
// - SocketError.SocketError
// - SocketError.SystemNotReady
// - SocketError.TypeNotFound
// - SocketError.VersionNotSupported

private static readonly Dictionary<Interop.Error, SocketError> s_nativeErrorToSocketError = new Dictionary<Interop.Error, SocketError>(NativeErrorToSocketErrorCount)
{
    { Interop.Error.EACCES, SocketError.AccessDenied },
    { Interop.Error.EADDRINUSE, SocketError.AddressAlreadyInUse },
    { Interop.Error.EADDRNOTAVAIL, SocketError.AddressNotAvailable },
    { Interop.Error.EAFNOSUPPORT, SocketError.AddressFamilyNotSupported },
    { Interop.Error.EAGAIN, SocketError.WouldBlock },
    { Interop.Error.EALREADY, SocketError.AlreadyInProgress },
    { Interop.Error.EBADF, SocketError.OperationAborted },
    { Interop.Error.ECANCELED, SocketError.OperationAborted },
    { Interop.Error.ECONNABORTED, SocketError.ConnectionAborted },
    { Interop.Error.ECONNREFUSED, SocketError.ConnectionRefused },
    { Interop.Error.ECONNRESET, SocketError.ConnectionReset },
    { Interop.Error.EDESTADDRREQ, SocketError.DestinationAddressRequired },
    { Interop.Error.EFAULT, SocketError.Fault },
    { Interop.Error.EHOSTDOWN, SocketError.HostDown },
    { Interop.Error.ENXIO, SocketError.HostNotFound }, // not perfect, but closest match available
    { Interop.Error.EHOSTUNREACH, SocketError.HostUnreachable },
    { Interop.Error.EINPROGRESS, SocketError.InProgress },
    { Interop.Error.EINTR, SocketError.Interrupted },
    { Interop.Error.EINVAL, SocketError.InvalidArgument },
    { Interop.Error.EISCONN, SocketError.IsConnected },
    { Interop.Error.EMFILE, SocketError.TooManyOpenSockets },
    { Interop.Error.EMSGSIZE, SocketError.MessageSize },
    { Interop.Error.ENETDOWN, SocketError.NetworkDown },
    { Interop.Error.ENETRESET, SocketError.NetworkReset },
    { Interop.Error.ENETUNREACH, SocketError.NetworkUnreachable },
    { Interop.Error.ENFILE, SocketError.TooManyOpenSockets },
    { Interop.Error.ENOBUFS, SocketError.NoBufferSpaceAvailable },
    { Interop.Error.ENODATA, SocketError.NoData },
    { Interop.Error.ENOENT, SocketError.AddressNotAvailable },
    { Interop.Error.ENOPROTOOPT, SocketError.ProtocolOption },
    { Interop.Error.ENOTCONN, SocketError.NotConnected },
    { Interop.Error.ENOTSOCK, SocketError.NotSocket },
    { Interop.Error.ENOTSUP, SocketError.OperationNotSupported },
    { Interop.Error.EPERM, SocketError.AccessDenied },
    { Interop.Error.EPIPE, SocketError.Shutdown },
    { Interop.Error.EPFNOSUPPORT, SocketError.ProtocolFamilyNotSupported },
    { Interop.Error.EPROTONOSUPPORT, SocketError.ProtocolNotSupported },
    { Interop.Error.EPROTOTYPE, SocketError.ProtocolType },
    { Interop.Error.ESOCKTNOSUPPORT, SocketError.SocketNotSupported },
    { Interop.Error.ESHUTDOWN, SocketError.Disconnecting },
    { Interop.Error.SUCCESS, SocketError.Success },
    { Interop.Error.ETIMEDOUT, SocketError.TimedOut },
};

private static readonly Dictionary<SocketError, Interop.Error> s_socketErrorToNativeError = new Dictionary<SocketError, Interop.Error>(SocketErrorToNativeErrorCount)
{
    // This is *mostly* an inverse mapping of s_nativeErrorToSocketError.  However, some options have multiple mappings and thus
    // can't be inverted directly.  Other options don't have a mapping from native to SocketError, but when presented with a SocketError,
    // we want to provide the closest relevant Error possible, e.g. EINPROGRESS maps to SocketError.InProgress, and vice versa, but
    // SocketError.IOPending also maps closest to EINPROGRESS.  As such, roundtripping won't necessarily provide the original value 100% of the time,
    // but it's the best we can do given the mismatch between Interop.Error and SocketError.

    { SocketError.AccessDenied, Interop.Error.EACCES}, // could also have been EPERM
    { SocketError.AddressAlreadyInUse, Interop.Error.EADDRINUSE  },
    { SocketError.AddressNotAvailable, Interop.Error.EADDRNOTAVAIL },
    { SocketError.AddressFamilyNotSupported, Interop.Error.EAFNOSUPPORT  },
    { SocketError.AlreadyInProgress, Interop.Error.EALREADY },
    { SocketError.ConnectionAborted, Interop.Error.ECONNABORTED },
    { SocketError.ConnectionRefused, Interop.Error.ECONNREFUSED },
    { SocketError.ConnectionReset, Interop.Error.ECONNRESET },
    { SocketError.DestinationAddressRequired, Interop.Error.EDESTADDRREQ },
    { SocketError.Disconnecting, Interop.Error.ESHUTDOWN },
    { SocketError.Fault, Interop.Error.EFAULT },
    { SocketError.HostDown, Interop.Error.EHOSTDOWN },
    { SocketError.HostNotFound, Interop.Error.EHOSTNOTFOUND },
    { SocketError.HostUnreachable, Interop.Error.EHOSTUNREACH },
    { SocketError.InProgress, Interop.Error.EINPROGRESS },
    { SocketError.Interrupted, Interop.Error.EINTR },
    { SocketError.InvalidArgument, Interop.Error.EINVAL },
    { SocketError.IOPending, Interop.Error.EINPROGRESS },
    { SocketError.IsConnected, Interop.Error.EISCONN },
    { SocketError.MessageSize, Interop.Error.EMSGSIZE },
    { SocketError.NetworkDown, Interop.Error.ENETDOWN },
    { SocketError.NetworkReset, Interop.Error.ENETRESET },
    { SocketError.NetworkUnreachable, Interop.Error.ENETUNREACH },
    { SocketError.NoBufferSpaceAvailable, Interop.Error.ENOBUFS },
    { SocketError.NoData, Interop.Error.ENODATA },
    { SocketError.NotConnected, Interop.Error.ENOTCONN },
    { SocketError.NotSocket, Interop.Error.ENOTSOCK },
    { SocketError.OperationAborted, Interop.Error.ECANCELED },
    { SocketError.OperationNotSupported, Interop.Error.ENOTSUP },
    { SocketError.ProtocolFamilyNotSupported, Interop.Error.EPFNOSUPPORT },
    { SocketError.ProtocolNotSupported, Interop.Error.EPROTONOSUPPORT },
    { SocketError.ProtocolOption, Interop.Error.ENOPROTOOPT },
    { SocketError.ProtocolType, Interop.Error.EPROTOTYPE },
    { SocketError.Shutdown, Interop.Error.EPIPE },
    { SocketError.SocketNotSupported, Interop.Error.ESOCKTNOSUPPORT },
    { SocketError.Success, Interop.Error.SUCCESS },
    { SocketError.TimedOut, Interop.Error.ETIMEDOUT },
    { SocketError.TooManyOpenSockets, Interop.Error.ENFILE }, // could also have been EMFILE
    { SocketError.TryAgain, Interop.Error.EAGAIN }, // not a perfect mapping, but better than nothing
    { SocketError.WouldBlock, Interop.Error.EAGAIN  },
};

internal static bool TryGetNativeErrorForSocketError(SocketError error, out Interop.Error errno)
{
    return s_socketErrorToNativeError.TryGetValue(error, out errno);
}

Once we have an instance of Interop.Error, we call interopErr.Info().RawErrno. The implementation of RawErrno can be found in Interop.Errors.cs:

internal int RawErrno
{
    get { return _rawErrno == -1 ? (_rawErrno = Interop.Sys.ConvertErrorPalToPlatform(_error)) : _rawErrno; }
}

[DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_ConvertErrorPalToPlatform")]
internal static extern int ConvertErrorPalToPlatform(Error error);

Here we are jumping to the native function SystemNative_ConvertErrorPalToPlatform that maps Error to the native integer code that is defined in errno.h. You can get all the values using the errno util. Here is a typical output on Linux:

$ errno -ls
EPERM 1 Operation not permitted
ENOENT 2 No such file or directory
ESRCH 3 No such process
EINTR 4 Interrupted system call
EIO 5 Input/output error
ENXIO 6 No such device or address
E2BIG 7 Argument list too long
ENOEXEC 8 Exec format error
EBADF 9 Bad file descriptor
ECHILD 10 No child processes
EAGAIN 11 Resource temporarily unavailable
ENOMEM 12 Cannot allocate memory
EACCES 13 Permission denied
EFAULT 14 Bad address
ENOTBLK 15 Block device required
EBUSY 16 Device or resource busy
EEXIST 17 File exists
EXDEV 18 Invalid cross-device link
ENODEV 19 No such device
ENOTDIR 20 Not a directory
EISDIR 21 Is a directory
EINVAL 22 Invalid argument
ENFILE 23 Too many open files in system
EMFILE 24 Too many open files
ENOTTY 25 Inappropriate ioctl for device
ETXTBSY 26 Text file busy
EFBIG 27 File too large
ENOSPC 28 No space left on device
ESPIPE 29 Illegal seek
EROFS 30 Read-only file system
EMLINK 31 Too many links
EPIPE 32 Broken pipe
EDOM 33 Numerical argument out of domain
ERANGE 34 Numerical result out of range
EDEADLK 35 Resource deadlock avoided
ENAMETOOLONG 36 File name too long
ENOLCK 37 No locks available
ENOSYS 38 Function not implemented
ENOTEMPTY 39 Directory not empty
ELOOP 40 Too many levels of symbolic links
EWOULDBLOCK 11 Resource temporarily unavailable
ENOMSG 42 No message of desired type
EIDRM 43 Identifier removed
ECHRNG 44 Channel number out of range
EL2NSYNC 45 Level 2 not synchronized
EL3HLT 46 Level 3 halted
EL3RST 47 Level 3 reset
ELNRNG 48 Link number out of range
EUNATCH 49 Protocol driver not attached
ENOCSI 50 No CSI structure available
EL2HLT 51 Level 2 halted
EBADE 52 Invalid exchange
EBADR 53 Invalid request descriptor
EXFULL 54 Exchange full
ENOANO 55 No anode
EBADRQC 56 Invalid request code
EBADSLT 57 Invalid slot
EDEADLOCK 35 Resource deadlock avoided
EBFONT 59 Bad font file format
ENOSTR 60 Device not a stream
ENODATA 61 No data available
ETIME 62 Timer expired
ENOSR 63 Out of streams resources
ENONET 64 Machine is not on the network
ENOPKG 65 Package not installed
EREMOTE 66 Object is remote
ENOLINK 67 Link has been severed
EADV 68 Advertise error
ESRMNT 69 Srmount error
ECOMM 70 Communication error on send
EPROTO 71 Protocol error
EMULTIHOP 72 Multihop attempted
EDOTDOT 73 RFS specific error
EBADMSG 74 Bad message
EOVERFLOW 75 Value too large for defined data type
ENOTUNIQ 76 Name not unique on network
EBADFD 77 File descriptor in bad state
EREMCHG 78 Remote address changed
ELIBACC 79 Can not access a needed shared library
ELIBBAD 80 Accessing a corrupted shared library
ELIBSCN 81 .lib section in a.out corrupted
ELIBMAX 82 Attempting to link in too many shared libraries
ELIBEXEC 83 Cannot exec a shared library directly
EILSEQ 84 Invalid or incomplete multibyte or wide character
ERESTART 85 Interrupted system call should be restarted
ESTRPIPE 86 Streams pipe error
EUSERS 87 Too many users
ENOTSOCK 88 Socket operation on non-socket
EDESTADDRREQ 89 Destination address required
EMSGSIZE 90 Message too long
EPROTOTYPE 91 Protocol wrong type for socket
ENOPROTOOPT 92 Protocol not available
EPROTONOSUPPORT 93 Protocol not supported
ESOCKTNOSUPPORT 94 Socket type not supported
EOPNOTSUPP 95 Operation not supported
EPFNOSUPPORT 96 Protocol family not supported
EAFNOSUPPORT 97 Address family not supported by protocol
EADDRINUSE 98 Address already in use
EADDRNOTAVAIL 99 Cannot assign requested address
ENETDOWN 100 Network is down
ENETUNREACH 101 Network is unreachable
ENETRESET 102 Network dropped connection on reset
ECONNABORTED 103 Software caused connection abort
ECONNRESET 104 Connection reset by peer
ENOBUFS 105 No buffer space available
EISCONN 106 Transport endpoint is already connected
ENOTCONN 107 Transport endpoint is not connected
ESHUTDOWN 108 Cannot send after transport endpoint shutdown
ETOOMANYREFS 109 Too many references: cannot splice
ETIMEDOUT 110 Connection timed out
ECONNREFUSED 111 Connection refused
EHOSTDOWN 112 Host is down
EHOSTUNREACH 113 No route to host
EALREADY 114 Operation already in progress
EINPROGRESS 115 Operation now in progress
ESTALE 116 Stale file handle
EUCLEAN 117 Structure needs cleaning
ENOTNAM 118 Not a XENIX named type file
ENAVAIL 119 No XENIX semaphores available
EISNAM 120 Is a named type file
EREMOTEIO 121 Remote I/O error
EDQUOT 122 Disk quota exceeded
ENOMEDIUM 123 No medium found
EMEDIUMTYPE 124 Wrong medium type
ECANCELED 125 Operation canceled
ENOKEY 126 Required key not available
EKEYEXPIRED 127 Key has expired
EKEYREVOKED 128 Key has been revoked
EKEYREJECTED 129 Key was rejected by service
EOWNERDEAD 130 Owner died
ENOTRECOVERABLE 131 State not recoverable
ERFKILL 132 Operation not possible due to RF-kill
EHWPOISON 133 Memory page has hardware error
ENOTSUP 95 Operation not supported

Note that errno may be not available by default in your Linux distro. For example, on Debian, you should call sudo apt-get install moreutils to get this utility.
Here is a typical output on macOS:

$ errno -ls
EPERM 1 Operation not permitted
ENOENT 2 No such file or directory
ESRCH 3 No such process
EINTR 4 Interrupted system call
EIO 5 Input/output error
ENXIO 6 Device not configured
E2BIG 7 Argument list too long
ENOEXEC 8 Exec format error
EBADF 9 Bad file descriptor
ECHILD 10 No child processes
EDEADLK 11 Resource deadlock avoided
ENOMEM 12 Cannot allocate memory
EACCES 13 Permission denied
EFAULT 14 Bad address
ENOTBLK 15 Block device required
EBUSY 16 Resource busy
EEXIST 17 File exists
EXDEV 18 Cross-device link
ENODEV 19 Operation not supported by device
ENOTDIR 20 Not a directory
EISDIR 21 Is a directory
EINVAL 22 Invalid argument
ENFILE 23 Too many open files in system
EMFILE 24 Too many open files
ENOTTY 25 Inappropriate ioctl for device
ETXTBSY 26 Text file busy
EFBIG 27 File too large
ENOSPC 28 No space left on device
ESPIPE 29 Illegal seek
EROFS 30 Read-only file system
EMLINK 31 Too many links
EPIPE 32 Broken pipe
EDOM 33 Numerical argument out of domain
ERANGE 34 Result too large
EAGAIN 35 Resource temporarily unavailable
EWOULDBLOCK 35 Resource temporarily unavailable
EINPROGRESS 36 Operation now in progress
EALREADY 37 Operation already in progress
ENOTSOCK 38 Socket operation on non-socket
EDESTADDRREQ 39 Destination address required
EMSGSIZE 40 Message too long
EPROTOTYPE 41 Protocol wrong type for socket
ENOPROTOOPT 42 Protocol not available
EPROTONOSUPPORT 43 Protocol not supported
ESOCKTNOSUPPORT 44 Socket type not supported
ENOTSUP 45 Operation not supported
EPFNOSUPPORT 46 Protocol family not supported
EAFNOSUPPORT 47 Address family not supported by protocol family
EADDRINUSE 48 Address already in use
EADDRNOTAVAIL 49 Can`t assign requested address
ENETDOWN 50 Network is down
ENETUNREACH 51 Network is unreachable
ENETRESET 52 Network dropped connection on reset
ECONNABORTED 53 Software caused connection abort
ECONNRESET 54 Connection reset by peer
ENOBUFS 55 No buffer space available
EISCONN 56 Socket is already connected
ENOTCONN 57 Socket is not connected
ESHUTDOWN 58 Can`t send after socket shutdown
ETOOMANYREFS 59 Too many references: can`t splice
ETIMEDOUT 60 Operation timed out
ECONNREFUSED 61 Connection refused
ELOOP 62 Too many levels of symbolic links
ENAMETOOLONG 63 File name too long
EHOSTDOWN 64 Host is down
EHOSTUNREACH 65 No route to host
ENOTEMPTY 66 Directory not empty
EPROCLIM 67 Too many processes
EUSERS 68 Too many users
EDQUOT 69 Disc quota exceeded
ESTALE 70 Stale NFS file handle
EREMOTE 71 Too many levels of remote in path
EBADRPC 72 RPC struct is bad
ERPCMISMATCH 73 RPC version wrong
EPROGUNAVAIL 74 RPC prog. not avail
EPROGMISMATCH 75 Program version wrong
EPROCUNAVAIL 76 Bad procedure for program
ENOLCK 77 No locks available
ENOSYS 78 Function not implemented
EFTYPE 79 Inappropriate file type or format
EAUTH 80 Authentication error
ENEEDAUTH 81 Need authenticator
EPWROFF 82 Device power is off
EDEVERR 83 Device error
EOVERFLOW 84 Value too large to be stored in data type
EBADEXEC 85 Bad executable (or shared library)
EBADARCH 86 Bad CPU type in executable
ESHLIBVERS 87 Shared library version mismatch
EBADMACHO 88 Malformed Mach-o file
ECANCELED 89 Operation canceled
EIDRM 90 Identifier removed
ENOMSG 91 No message of desired type
EILSEQ 92 Illegal byte sequence
ENOATTR 93 Attribute not found
EBADMSG 94 Bad message
EMULTIHOP 95 EMULTIHOP (Reserved)
ENODATA 96 No message available on STREAM
ENOLINK 97 ENOLINK (Reserved)
ENOSR 98 No STREAM resources
ENOSTR 99 Not a STREAM
EPROTO 100 Protocol error
ETIME 101 STREAM ioctl timeout
EOPNOTSUPP 102 Operation not supported on socket
ENOPOLICY 103 Policy not found
ENOTRECOVERABLE 104 State not recoverable
EOWNERDEAD 105 Previous owner died
EQFULL 106 Interface output queue is full
ELAST 106 Interface output queue is full

Hooray! We’ve finished our fascinating journey into the internals of socket error codes. Now you know where .NET is getting the native error code for each SocketException from!

ErrorCode

The ErrorCode property is the most boring one, as it always returns NativeErrorCode.
.NET Framework, Mono 6.8.0.105:

public override int ErrorCode {
    //
    // the base class returns the HResult with this property
    // we need the Win32 Error Code, hence the override.
    //
    get {
        return NativeErrorCode;
    }
}

In .NET Core 3.1.3:

public override int ErrorCode => base.NativeErrorCode;

Writing cross-platform socket error handling

Circling back to the original method we started this post with, we rewrote ShouldRetryConnection as follows:

protected virtual bool ShouldRetryConnection(Exception ex)
{
    if (ex is SocketException sx)
        return sx.SocketErrorCode == SocketError.ConnectionRefused;
    return false;
}

There was a lot of work involved in tracking down the error code to check against, but in the end, our code is much more readable now. Adding to that, this method is now also completely cross-platform, and works correctly on any runtime.

Overview of the native error codes

In some situations, you may want to have a table with native error codes on different operating systems. We can get these values with the following code snippet:

var allErrors = Enum.GetValues(typeof(SocketError)).Cast<SocketError>().ToList();
var maxNameWidth = allErrors.Select(x => x.ToString().Length).Max();
foreach (var socketError in allErrors)
{
    var name = socketError.ToString().PadRight(maxNameWidth);
    var code = new SocketException((int) socketError).NativeErrorCode.ToString().PadLeft(7);
    Console.WriteLine($TEXT$quot;| {name} | {code} |");
}

We executed this program on Windows, Linux, and macOS. Here are the aggregated results:

SocketError	Windows	Linux	macOS
Success	0	0	0
OperationAborted	995	125	89
IOPending	997	115	36
Interrupted	10004	4	4
AccessDenied	10013	13	13
Fault	10014	14	14
InvalidArgument	10022	22	22
TooManyOpenSockets	10024	23	23
WouldBlock	10035	11	35
InProgress	10036	115	36
AlreadyInProgress	10037	114	37
NotSocket	10038	88	38
DestinationAddressRequired	10039	89	39
MessageSize	10040	90	40
ProtocolType	10041	91	41
ProtocolOption	10042	92	42
ProtocolNotSupported	10043	93	43
SocketNotSupported	10044	94	44
OperationNotSupported	10045	95	45
ProtocolFamilyNotSupported	10046	96	46
AddressFamilyNotSupported	10047	97	47
AddressAlreadyInUse	10048	98	48
AddressNotAvailable	10049	99	49
NetworkDown	10050	100	50
NetworkUnreachable	10051	101	51
NetworkReset	10052	102	52
ConnectionAborted	10053	103	53
ConnectionReset	10054	104	54
NoBufferSpaceAvailable	10055	105	55
IsConnected	10056	106	56
NotConnected	10057	107	57
Shutdown	10058	32	32
TimedOut	10060	110	60
ConnectionRefused	10061	111	61
HostDown	10064	112	64
HostUnreachable	10065	113	65
ProcessLimit	10067	10067	10067
SystemNotReady	10091	10091	10091
VersionNotSupported	10092	10092	10092
NotInitialized	10093	10093	10093
Disconnecting	10101	108	58
TypeNotFound	10109	10109	10109
HostNotFound	11001	-131073	-131073
TryAgain	11002	11	35
NoRecovery	11003	11003	11003
NoData	11004	61	96
SocketError	-1	-1	-1

This table may be useful if you work with native socket error codes.

Summary

From this investigation, we’ve learned the following:

SocketException.SocketErrorCode returns a value from the SocketError enum. The numerical values of the enum elements always correspond to the Windows socket error codes.
SocketException.ErrorCode always returns SocketException.NativeErrorCode.
SocketException.NativeErrorCode on .NET Framework and Mono always corresponds to the Windows error codes (even if you are using Mono on Unix). On .NET Core, SocketException.NativeErrorCode equals the corresponding native error code from the current operating system.

A few practical recommendations:

If you want to write portable code, always use SocketException.SocketErrorCode and compare it with the values of SocketError. Never use raw numerical error codes.
If you want to get the native error code on .NET Core (e.g., for passing to another native program), use SocketException.NativeErrorCode. Remember that different Unix-based operating systems (e.g., Linux, macOS, Solaris) have different native code sets. You can get the exact values of the native error codes by using the errno command.

References

Microsoft Docs: Windows Sockets Error Codes
IBM Knowledge Center: TCP/IP error codes
MariaDB: Operating System Error Codes
gnu.org: Error Codes
Stackoverflow: Identical Error Codes

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Источник

This blog post was originally posted on JetBrains .NET blog.

protected virtual bool ShouldRetryConnection (Exception ex, int attemptNumber)
{
    var sx = ex as SocketException;
    if (sx != null) {
        if (sx.ErrorCode == 10061) //connection refused
            return true;
    }
    return false;
}

SocketError SocketErrorCode: Gets the error code that is associated with this exception.
int ErrorCode: Gets the error code that is associated with this exception.
int NativeErrorCode: Gets the Win32 error code associated with this exception.

Digging into the problem

Let’s start with the following program, which prints error code property values for SocketError.ConnectionRefused:

var se = new SocketException((int) SocketError.ConnectionRefused);
Console.WriteLine((int)se.SocketErrorCode);
Console.WriteLine(se.ErrorCode);
Console.WriteLine(se.NativeErrorCode);

If we run it on Windows, we will get the same value on .NET Framework, Mono, and .NET Core:

	SocketErrorCode	ErrorCode	NativeErrorCode
.NET Framework	10061	10061	10061
Mono	10061	10061	10061
.NET Core	10061	10061	10061

10061 corresponds to the code of the connection refused socket error code in Windows (also known as WSAECONNREFUSED).
Now let’s run the same program on Linux:

	SocketErrorCode	ErrorCode	NativeErrorCode
Mono	10061	10061	10061
.NET Core	10061	111	111

	SocketErrorCode	ErrorCode	NativeErrorCode
Mono	10061	10061	10061
.NET Core	10061	61	61

AIX: 79
HP-UX: 239
Solaris: 146

For a better understanding of what’s going on, let’s check out the source code of all the properties.

SocketErrorCode

public enum SocketError
{
    SocketError = -1, // 0xFFFFFFFF
    Success = 0,
    OperationAborted = 995, // 0x000003E3
    IOPending = 997, // 0x000003E5
    Interrupted = 10004, // 0x00002714
    AccessDenied = 10013, // 0x0000271D
    Fault = 10014, // 0x0000271E
    InvalidArgument = 10022, // 0x00002726
    TooManyOpenSockets = 10024, // 0x00002728
    WouldBlock = 10035, // 0x00002733
    InProgress = 10036, // 0x00002734
    AlreadyInProgress = 10037, // 0x00002735
    NotSocket = 10038, // 0x00002736
    DestinationAddressRequired = 10039, // 0x00002737
    MessageSize = 10040, // 0x00002738
    ProtocolType = 10041, // 0x00002739
    ProtocolOption = 10042, // 0x0000273A
    ProtocolNotSupported = 10043, // 0x0000273B
    SocketNotSupported = 10044, // 0x0000273C
    OperationNotSupported = 10045, // 0x0000273D
    ProtocolFamilyNotSupported = 10046, // 0x0000273E
    AddressFamilyNotSupported = 10047, // 0x0000273F
    AddressAlreadyInUse = 10048, // 0x00002740
    AddressNotAvailable = 10049, // 0x00002741
    NetworkDown = 10050, // 0x00002742
    NetworkUnreachable = 10051, // 0x00002743
    NetworkReset = 10052, // 0x00002744
    ConnectionAborted = 10053, // 0x00002745
    ConnectionReset = 10054, // 0x00002746
    NoBufferSpaceAvailable = 10055, // 0x00002747
    IsConnected = 10056, // 0x00002748
    NotConnected = 10057, // 0x00002749
    Shutdown = 10058, // 0x0000274A
    TimedOut = 10060, // 0x0000274C
    ConnectionRefused = 10061, // 0x0000274D
    HostDown = 10064, // 0x00002750
    HostUnreachable = 10065, // 0x00002751
    ProcessLimit = 10067, // 0x00002753
    SystemNotReady = 10091, // 0x0000276B
    VersionNotSupported = 10092, // 0x0000276C
    NotInitialized = 10093, // 0x0000276D
    Disconnecting = 10101, // 0x00002775
    TypeNotFound = 10109, // 0x0000277D
    HostNotFound = 11001, // 0x00002AF9
    TryAgain = 11002, // 0x00002AFA
    NoRecovery = 11003, // 0x00002AFB
    NoData = 11004, // 0x00002AFC
}

These values correspond to the Windows Sockets Error Codes.

NativeErrorCode

In .NET Framework and Mono, SocketErrorCode and NativeErrorCode always have the same values:

public SocketError SocketErrorCode {
    //
    // the base class returns the HResult with this property
    // we need the Win32 Error Code, hence the override.
    //
    get {
        return (SocketError)NativeErrorCode;
    }
}

In .NET Core, the native code is calculated in the constructor (see SocketException.cs#L20):

public SocketException(int errorCode) : this((SocketError)errorCode)
// ...
internal SocketException(SocketError socketError) : base(GetNativeErrorForSocketError(socketError))

The Windows implementation of GetNativeErrorForSocketError is trivial (see SocketException.Windows.cs):

private static int GetNativeErrorForSocketError(SocketError error)
{
    // SocketError values map directly to Win32 error codes
    return (int)error;
}

The Unix implementation is more complicated (see SocketException.Unix.cs):

private static int GetNativeErrorForSocketError(SocketError error)
{
    int nativeErr = (int)error;
    if (error != SocketError.SocketError)
    {
        Interop.Error interopErr;

        // If an interop error was not found, then don't invoke Info().RawErrno as that will fail with assert.
        if (SocketErrorPal.TryGetNativeErrorForSocketError(error, out interopErr))
        {
            nativeErr = interopErr.Info().RawErrno;
        }
    }

    return nativeErr;
}

private const int NativeErrorToSocketErrorCount = 42;
private const int SocketErrorToNativeErrorCount = 40;

// No Interop.Errors are included for the following SocketErrors, as there's no good mapping:
// - SocketError.NoRecovery
// - SocketError.NotInitialized
// - SocketError.ProcessLimit
// - SocketError.SocketError
// - SocketError.SystemNotReady
// - SocketError.TypeNotFound
// - SocketError.VersionNotSupported

private static readonly Dictionary&lt;Interop.Error, SocketError&gt; s_nativeErrorToSocketError = new Dictionary&lt;Interop.Error, SocketError&gt;(NativeErrorToSocketErrorCount)
{
    { Interop.Error.EACCES, SocketError.AccessDenied },
    { Interop.Error.EADDRINUSE, SocketError.AddressAlreadyInUse },
    { Interop.Error.EADDRNOTAVAIL, SocketError.AddressNotAvailable },
    { Interop.Error.EAFNOSUPPORT, SocketError.AddressFamilyNotSupported },
    { Interop.Error.EAGAIN, SocketError.WouldBlock },
    { Interop.Error.EALREADY, SocketError.AlreadyInProgress },
    { Interop.Error.EBADF, SocketError.OperationAborted },
    { Interop.Error.ECANCELED, SocketError.OperationAborted },
    { Interop.Error.ECONNABORTED, SocketError.ConnectionAborted },
    { Interop.Error.ECONNREFUSED, SocketError.ConnectionRefused },
    { Interop.Error.ECONNRESET, SocketError.ConnectionReset },
    { Interop.Error.EDESTADDRREQ, SocketError.DestinationAddressRequired },
    { Interop.Error.EFAULT, SocketError.Fault },
    { Interop.Error.EHOSTDOWN, SocketError.HostDown },
    { Interop.Error.ENXIO, SocketError.HostNotFound }, // not perfect, but closest match available
    { Interop.Error.EHOSTUNREACH, SocketError.HostUnreachable },
    { Interop.Error.EINPROGRESS, SocketError.InProgress },
    { Interop.Error.EINTR, SocketError.Interrupted },
    { Interop.Error.EINVAL, SocketError.InvalidArgument },
    { Interop.Error.EISCONN, SocketError.IsConnected },
    { Interop.Error.EMFILE, SocketError.TooManyOpenSockets },
    { Interop.Error.EMSGSIZE, SocketError.MessageSize },
    { Interop.Error.ENETDOWN, SocketError.NetworkDown },
    { Interop.Error.ENETRESET, SocketError.NetworkReset },
    { Interop.Error.ENETUNREACH, SocketError.NetworkUnreachable },
    { Interop.Error.ENFILE, SocketError.TooManyOpenSockets },
    { Interop.Error.ENOBUFS, SocketError.NoBufferSpaceAvailable },
    { Interop.Error.ENODATA, SocketError.NoData },
    { Interop.Error.ENOENT, SocketError.AddressNotAvailable },
    { Interop.Error.ENOPROTOOPT, SocketError.ProtocolOption },
    { Interop.Error.ENOTCONN, SocketError.NotConnected },
    { Interop.Error.ENOTSOCK, SocketError.NotSocket },
    { Interop.Error.ENOTSUP, SocketError.OperationNotSupported },
    { Interop.Error.EPERM, SocketError.AccessDenied },
    { Interop.Error.EPIPE, SocketError.Shutdown },
    { Interop.Error.EPFNOSUPPORT, SocketError.ProtocolFamilyNotSupported },
    { Interop.Error.EPROTONOSUPPORT, SocketError.ProtocolNotSupported },
    { Interop.Error.EPROTOTYPE, SocketError.ProtocolType },
    { Interop.Error.ESOCKTNOSUPPORT, SocketError.SocketNotSupported },
    { Interop.Error.ESHUTDOWN, SocketError.Disconnecting },
    { Interop.Error.SUCCESS, SocketError.Success },
    { Interop.Error.ETIMEDOUT, SocketError.TimedOut },
};

private static readonly Dictionary&lt;SocketError, Interop.Error&gt; s_socketErrorToNativeError = new Dictionary&lt;SocketError, Interop.Error&gt;(SocketErrorToNativeErrorCount)
{
    // This is *mostly* an inverse mapping of s_nativeErrorToSocketError.  However, some options have multiple mappings and thus
    // can't be inverted directly.  Other options don't have a mapping from native to SocketError, but when presented with a SocketError,
    // we want to provide the closest relevant Error possible, e.g. EINPROGRESS maps to SocketError.InProgress, and vice versa, but
    // SocketError.IOPending also maps closest to EINPROGRESS.  As such, roundtripping won't necessarily provide the original value 100% of the time,
    // but it's the best we can do given the mismatch between Interop.Error and SocketError.

    { SocketError.AccessDenied, Interop.Error.EACCES}, // could also have been EPERM
    { SocketError.AddressAlreadyInUse, Interop.Error.EADDRINUSE  },
    { SocketError.AddressNotAvailable, Interop.Error.EADDRNOTAVAIL },
    { SocketError.AddressFamilyNotSupported, Interop.Error.EAFNOSUPPORT  },
    { SocketError.AlreadyInProgress, Interop.Error.EALREADY },
    { SocketError.ConnectionAborted, Interop.Error.ECONNABORTED },
    { SocketError.ConnectionRefused, Interop.Error.ECONNREFUSED },
    { SocketError.ConnectionReset, Interop.Error.ECONNRESET },
    { SocketError.DestinationAddressRequired, Interop.Error.EDESTADDRREQ },
    { SocketError.Disconnecting, Interop.Error.ESHUTDOWN },
    { SocketError.Fault, Interop.Error.EFAULT },
    { SocketError.HostDown, Interop.Error.EHOSTDOWN },
    { SocketError.HostNotFound, Interop.Error.EHOSTNOTFOUND },
    { SocketError.HostUnreachable, Interop.Error.EHOSTUNREACH },
    { SocketError.InProgress, Interop.Error.EINPROGRESS },
    { SocketError.Interrupted, Interop.Error.EINTR },
    { SocketError.InvalidArgument, Interop.Error.EINVAL },
    { SocketError.IOPending, Interop.Error.EINPROGRESS },
    { SocketError.IsConnected, Interop.Error.EISCONN },
    { SocketError.MessageSize, Interop.Error.EMSGSIZE },
    { SocketError.NetworkDown, Interop.Error.ENETDOWN },
    { SocketError.NetworkReset, Interop.Error.ENETRESET },
    { SocketError.NetworkUnreachable, Interop.Error.ENETUNREACH },
    { SocketError.NoBufferSpaceAvailable, Interop.Error.ENOBUFS },
    { SocketError.NoData, Interop.Error.ENODATA },
    { SocketError.NotConnected, Interop.Error.ENOTCONN },
    { SocketError.NotSocket, Interop.Error.ENOTSOCK },
    { SocketError.OperationAborted, Interop.Error.ECANCELED },
    { SocketError.OperationNotSupported, Interop.Error.ENOTSUP },
    { SocketError.ProtocolFamilyNotSupported, Interop.Error.EPFNOSUPPORT },
    { SocketError.ProtocolNotSupported, Interop.Error.EPROTONOSUPPORT },
    { SocketError.ProtocolOption, Interop.Error.ENOPROTOOPT },
    { SocketError.ProtocolType, Interop.Error.EPROTOTYPE },
    { SocketError.Shutdown, Interop.Error.EPIPE },
    { SocketError.SocketNotSupported, Interop.Error.ESOCKTNOSUPPORT },
    { SocketError.Success, Interop.Error.SUCCESS },
    { SocketError.TimedOut, Interop.Error.ETIMEDOUT },
    { SocketError.TooManyOpenSockets, Interop.Error.ENFILE }, // could also have been EMFILE
    { SocketError.TryAgain, Interop.Error.EAGAIN }, // not a perfect mapping, but better than nothing
    { SocketError.WouldBlock, Interop.Error.EAGAIN  },
};

internal static bool TryGetNativeErrorForSocketError(SocketError error, out Interop.Error errno)
{
    return s_socketErrorToNativeError.TryGetValue(error, out errno);
}

Once we have an instance of Interop.Error, we call interopErr.Info().RawErrno. The implementation of RawErrno can be found in Interop.Errors.cs:

internal int RawErrno
{
    get { return _rawErrno == -1 ? (_rawErrno = Interop.Sys.ConvertErrorPalToPlatform(_error)) : _rawErrno; }
}

[DllImport(Libraries.SystemNative, EntryPoint = "SystemNative_ConvertErrorPalToPlatform")]
internal static extern int ConvertErrorPalToPlatform(Error error);

$ errno -ls
EPERM 1 Operation not permitted
ENOENT 2 No such file or directory
ESRCH 3 No such process
EINTR 4 Interrupted system call
EIO 5 Input/output error
ENXIO 6 No such device or address
E2BIG 7 Argument list too long
ENOEXEC 8 Exec format error
EBADF 9 Bad file descriptor
ECHILD 10 No child processes
EAGAIN 11 Resource temporarily unavailable
ENOMEM 12 Cannot allocate memory
EACCES 13 Permission denied
EFAULT 14 Bad address
ENOTBLK 15 Block device required
EBUSY 16 Device or resource busy
EEXIST 17 File exists
EXDEV 18 Invalid cross-device link
ENODEV 19 No such device
ENOTDIR 20 Not a directory
EISDIR 21 Is a directory
EINVAL 22 Invalid argument
ENFILE 23 Too many open files in system
EMFILE 24 Too many open files
ENOTTY 25 Inappropriate ioctl for device
ETXTBSY 26 Text file busy
EFBIG 27 File too large
ENOSPC 28 No space left on device
ESPIPE 29 Illegal seek
EROFS 30 Read-only file system
EMLINK 31 Too many links
EPIPE 32 Broken pipe
EDOM 33 Numerical argument out of domain
ERANGE 34 Numerical result out of range
EDEADLK 35 Resource deadlock avoided
ENAMETOOLONG 36 File name too long
ENOLCK 37 No locks available
ENOSYS 38 Function not implemented
ENOTEMPTY 39 Directory not empty
ELOOP 40 Too many levels of symbolic links
EWOULDBLOCK 11 Resource temporarily unavailable
ENOMSG 42 No message of desired type
EIDRM 43 Identifier removed
ECHRNG 44 Channel number out of range
EL2NSYNC 45 Level 2 not synchronized
EL3HLT 46 Level 3 halted
EL3RST 47 Level 3 reset
ELNRNG 48 Link number out of range
EUNATCH 49 Protocol driver not attached
ENOCSI 50 No CSI structure available
EL2HLT 51 Level 2 halted
EBADE 52 Invalid exchange
EBADR 53 Invalid request descriptor
EXFULL 54 Exchange full
ENOANO 55 No anode
EBADRQC 56 Invalid request code
EBADSLT 57 Invalid slot
EDEADLOCK 35 Resource deadlock avoided
EBFONT 59 Bad font file format
ENOSTR 60 Device not a stream
ENODATA 61 No data available
ETIME 62 Timer expired
ENOSR 63 Out of streams resources
ENONET 64 Machine is not on the network
ENOPKG 65 Package not installed
EREMOTE 66 Object is remote
ENOLINK 67 Link has been severed
EADV 68 Advertise error
ESRMNT 69 Srmount error
ECOMM 70 Communication error on send
EPROTO 71 Protocol error
EMULTIHOP 72 Multihop attempted
EDOTDOT 73 RFS specific error
EBADMSG 74 Bad message
EOVERFLOW 75 Value too large for defined data type
ENOTUNIQ 76 Name not unique on network
EBADFD 77 File descriptor in bad state
EREMCHG 78 Remote address changed
ELIBACC 79 Can not access a needed shared library
ELIBBAD 80 Accessing a corrupted shared library
ELIBSCN 81 .lib section in a.out corrupted
ELIBMAX 82 Attempting to link in too many shared libraries
ELIBEXEC 83 Cannot exec a shared library directly
EILSEQ 84 Invalid or incomplete multibyte or wide character
ERESTART 85 Interrupted system call should be restarted
ESTRPIPE 86 Streams pipe error
EUSERS 87 Too many users
ENOTSOCK 88 Socket operation on non-socket
EDESTADDRREQ 89 Destination address required
EMSGSIZE 90 Message too long
EPROTOTYPE 91 Protocol wrong type for socket
ENOPROTOOPT 92 Protocol not available
EPROTONOSUPPORT 93 Protocol not supported
ESOCKTNOSUPPORT 94 Socket type not supported
EOPNOTSUPP 95 Operation not supported
EPFNOSUPPORT 96 Protocol family not supported
EAFNOSUPPORT 97 Address family not supported by protocol
EADDRINUSE 98 Address already in use
EADDRNOTAVAIL 99 Cannot assign requested address
ENETDOWN 100 Network is down
ENETUNREACH 101 Network is unreachable
ENETRESET 102 Network dropped connection on reset
ECONNABORTED 103 Software caused connection abort
ECONNRESET 104 Connection reset by peer
ENOBUFS 105 No buffer space available
EISCONN 106 Transport endpoint is already connected
ENOTCONN 107 Transport endpoint is not connected
ESHUTDOWN 108 Cannot send after transport endpoint shutdown
ETOOMANYREFS 109 Too many references: cannot splice
ETIMEDOUT 110 Connection timed out
ECONNREFUSED 111 Connection refused
EHOSTDOWN 112 Host is down
EHOSTUNREACH 113 No route to host
EALREADY 114 Operation already in progress
EINPROGRESS 115 Operation now in progress
ESTALE 116 Stale file handle
EUCLEAN 117 Structure needs cleaning
ENOTNAM 118 Not a XENIX named type file
ENAVAIL 119 No XENIX semaphores available
EISNAM 120 Is a named type file
EREMOTEIO 121 Remote I/O error
EDQUOT 122 Disk quota exceeded
ENOMEDIUM 123 No medium found
EMEDIUMTYPE 124 Wrong medium type
ECANCELED 125 Operation canceled
ENOKEY 126 Required key not available
EKEYEXPIRED 127 Key has expired
EKEYREVOKED 128 Key has been revoked
EKEYREJECTED 129 Key was rejected by service
EOWNERDEAD 130 Owner died
ENOTRECOVERABLE 131 State not recoverable
ERFKILL 132 Operation not possible due to RF-kill
EHWPOISON 133 Memory page has hardware error
ENOTSUP 95 Operation not supported

$ errno -ls
EPERM 1 Operation not permitted
ENOENT 2 No such file or directory
ESRCH 3 No such process
EINTR 4 Interrupted system call
EIO 5 Input/output error
ENXIO 6 Device not configured
E2BIG 7 Argument list too long
ENOEXEC 8 Exec format error
EBADF 9 Bad file descriptor
ECHILD 10 No child processes
EDEADLK 11 Resource deadlock avoided
ENOMEM 12 Cannot allocate memory
EACCES 13 Permission denied
EFAULT 14 Bad address
ENOTBLK 15 Block device required
EBUSY 16 Resource busy
EEXIST 17 File exists
EXDEV 18 Cross-device link
ENODEV 19 Operation not supported by device
ENOTDIR 20 Not a directory
EISDIR 21 Is a directory
EINVAL 22 Invalid argument
ENFILE 23 Too many open files in system
EMFILE 24 Too many open files
ENOTTY 25 Inappropriate ioctl for device
ETXTBSY 26 Text file busy
EFBIG 27 File too large
ENOSPC 28 No space left on device
ESPIPE 29 Illegal seek
EROFS 30 Read-only file system
EMLINK 31 Too many links
EPIPE 32 Broken pipe
EDOM 33 Numerical argument out of domain
ERANGE 34 Result too large
EAGAIN 35 Resource temporarily unavailable
EWOULDBLOCK 35 Resource temporarily unavailable
EINPROGRESS 36 Operation now in progress
EALREADY 37 Operation already in progress
ENOTSOCK 38 Socket operation on non-socket
EDESTADDRREQ 39 Destination address required
EMSGSIZE 40 Message too long
EPROTOTYPE 41 Protocol wrong type for socket
ENOPROTOOPT 42 Protocol not available
EPROTONOSUPPORT 43 Protocol not supported
ESOCKTNOSUPPORT 44 Socket type not supported
ENOTSUP 45 Operation not supported
EPFNOSUPPORT 46 Protocol family not supported
EAFNOSUPPORT 47 Address family not supported by protocol family
EADDRINUSE 48 Address already in use
EADDRNOTAVAIL 49 Can`t assign requested address
ENETDOWN 50 Network is down
ENETUNREACH 51 Network is unreachable
ENETRESET 52 Network dropped connection on reset
ECONNABORTED 53 Software caused connection abort
ECONNRESET 54 Connection reset by peer
ENOBUFS 55 No buffer space available
EISCONN 56 Socket is already connected
ENOTCONN 57 Socket is not connected
ESHUTDOWN 58 Can`t send after socket shutdown
ETOOMANYREFS 59 Too many references: can`t splice
ETIMEDOUT 60 Operation timed out
ECONNREFUSED 61 Connection refused
ELOOP 62 Too many levels of symbolic links
ENAMETOOLONG 63 File name too long
EHOSTDOWN 64 Host is down
EHOSTUNREACH 65 No route to host
ENOTEMPTY 66 Directory not empty
EPROCLIM 67 Too many processes
EUSERS 68 Too many users
EDQUOT 69 Disc quota exceeded
ESTALE 70 Stale NFS file handle
EREMOTE 71 Too many levels of remote in path
EBADRPC 72 RPC struct is bad
ERPCMISMATCH 73 RPC version wrong
EPROGUNAVAIL 74 RPC prog. not avail
EPROGMISMATCH 75 Program version wrong
EPROCUNAVAIL 76 Bad procedure for program
ENOLCK 77 No locks available
ENOSYS 78 Function not implemented
EFTYPE 79 Inappropriate file type or format
EAUTH 80 Authentication error
ENEEDAUTH 81 Need authenticator
EPWROFF 82 Device power is off
EDEVERR 83 Device error
EOVERFLOW 84 Value too large to be stored in data type
EBADEXEC 85 Bad executable (or shared library)
EBADARCH 86 Bad CPU type in executable
ESHLIBVERS 87 Shared library version mismatch
EBADMACHO 88 Malformed Mach-o file
ECANCELED 89 Operation canceled
EIDRM 90 Identifier removed
ENOMSG 91 No message of desired type
EILSEQ 92 Illegal byte sequence
ENOATTR 93 Attribute not found
EBADMSG 94 Bad message
EMULTIHOP 95 EMULTIHOP (Reserved)
ENODATA 96 No message available on STREAM
ENOLINK 97 ENOLINK (Reserved)
ENOSR 98 No STREAM resources
ENOSTR 99 Not a STREAM
EPROTO 100 Protocol error
ETIME 101 STREAM ioctl timeout
EOPNOTSUPP 102 Operation not supported on socket
ENOPOLICY 103 Policy not found
ENOTRECOVERABLE 104 State not recoverable
EOWNERDEAD 105 Previous owner died
EQFULL 106 Interface output queue is full
ELAST 106 Interface output queue is full

Hooray! We’ve finished our fascinating journey into the internals of socket error codes. Now you know where .NET is getting the native error code for each SocketException from!

ErrorCode

The ErrorCode property is the most boring one, as it always returns NativeErrorCode.
.NET Framework, Mono 6.8.0.105:

public override int ErrorCode {
    //
    // the base class returns the HResult with this property
    // we need the Win32 Error Code, hence the override.
    //
    get {
        return NativeErrorCode;
    }
}

In .NET Core 3.1.3:

public override int ErrorCode =&gt; base.NativeErrorCode;

Writing cross-platform socket error handling

Circling back to the original method we started this post with, we rewrote ShouldRetryConnection as follows:

protected virtual bool ShouldRetryConnection(Exception ex)
{
    if (ex is SocketException sx)
        return sx.SocketErrorCode == SocketError.ConnectionRefused;
    return false;
}

Overview of the native error codes

In some situations, you may want to have a table with native error codes on different operating systems. We can get these values with the following code snippet:

var allErrors = Enum.GetValues(typeof(SocketError)).Cast&lt;SocketError&gt;().ToList();
var maxNameWidth = allErrors.Select(x =&gt; x.ToString().Length).Max();
foreach (var socketError in allErrors)
{
    var name = socketError.ToString().PadRight(maxNameWidth);
    var code = new SocketException((int) socketError).NativeErrorCode.ToString().PadLeft(7);
    Console.WriteLine("| {name} | {code} |");
}

We executed this program on Windows, Linux, and macOS. Here are the aggregated results:

SocketError	Windows	Linux	macOS
Success	0	0	0
OperationAborted	995	125	89
IOPending	997	115	36
Interrupted	10004	4	4
AccessDenied	10013	13	13
Fault	10014	14	14
InvalidArgument	10022	22	22
TooManyOpenSockets	10024	23	23
WouldBlock	10035	11	35
InProgress	10036	115	36
AlreadyInProgress	10037	114	37
NotSocket	10038	88	38
DestinationAddressRequired	10039	89	39
MessageSize	10040	90	40
ProtocolType	10041	91	41
ProtocolOption	10042	92	42
ProtocolNotSupported	10043	93	43
SocketNotSupported	10044	94	44
OperationNotSupported	10045	95	45
ProtocolFamilyNotSupported	10046	96	46
AddressFamilyNotSupported	10047	97	47
AddressAlreadyInUse	10048	98	48
AddressNotAvailable	10049	99	49
NetworkDown	10050	100	50
NetworkUnreachable	10051	101	51
NetworkReset	10052	102	52
ConnectionAborted	10053	103	53
ConnectionReset	10054	104	54
NoBufferSpaceAvailable	10055	105	55
IsConnected	10056	106	56
NotConnected	10057	107	57
Shutdown	10058	32	32
TimedOut	10060	110	60
ConnectionRefused	10061	111	61
HostDown	10064	112	64
HostUnreachable	10065	113	65
ProcessLimit	10067	10067	10067
SystemNotReady	10091	10091	10091
VersionNotSupported	10092	10092	10092
NotInitialized	10093	10093	10093
Disconnecting	10101	108	58
TypeNotFound	10109	10109	10109
HostNotFound	11001	-131073	-131073
TryAgain	11002	11	35
NoRecovery	11003	11003	11003
NoData	11004	61	96
SocketError	-1	-1	-1

This table may be useful if you work with native socket error codes.

Summary

From this investigation, we’ve learned the following:

SocketException.SocketErrorCode returns a value from the SocketError enum. The numerical values of the enum elements always correspond to the Windows socket error codes.
SocketException.ErrorCode always returns SocketException.NativeErrorCode.
SocketException.NativeErrorCode on .NET Framework and Mono always corresponds to the Windows error codes (even if you are using Mono on Unix). On .NET Core, SocketException.NativeErrorCode equals the corresponding native error code from the current operating system.

A few practical recommendations:

If you want to write portable code, always use SocketException.SocketErrorCode and compare it with the values of SocketError. Never use raw numerical error codes.
If you want to get the native error code on .NET Core (e.g., for passing to another native program), use SocketException.NativeErrorCode. Remember that different Unix-based operating systems (e.g., Linux, macOS, Solaris) have different native code sets. You can get the exact values of the native error codes by using the errno command.

References

Microsoft Docs: Windows Sockets Error Codes
IBM Knowledge Center: TCP/IP error codes
MariaDB: Operating System Error Codes
gnu.org: Error Codes
Stackoverflow: Identical Error Codes

Источник

Back to Miscellaneous

Windows Sockets Error
Codes

Most Windows Sockets 2 functions do not return the specific
cause of an error when the function returns. For information, see the Handling Winsock Errors topic.

The WSAGetLastError function
returns the last error that occurred for the calling thread. When a particular
Windows Sockets function indicates an error has occurred, this function should
be called immediately to retrieve the extended error code for the failing
function call. These error codes and a short text description associated with
an error code are defined in the Winerror.h header file. The FormatMessage function
can be used to obtain the message string for the returned error.

For information on how to handle error codes when porting socket
applications to Winsock, see [http://msdn.microsoft.com/en-us/library/windows/desktop/ms737828(v=vs.85).aspx «Error Codes — errno, h_errno and
WSAGetLastError»].

The following list describes the possible error codes returned
by the WSAGetLastError function.
Errors are listed in numerical order with the error macro name. Some error
codes defined in the Winsock2.h header file are not returned
from any function.

Return
code/value

Description

WSA_INVALID_HANDLE

Specified
event object handle is invalid.

An
application attempts to use an event object, but the specified handle is not
valid. Note that this error is returned by the operating system, so the error
number may change in future releases of Windows.

WSA_NOT_ENOUGH_MEMORY

Insufficient
memory available.

An
application used a Windows Sockets function that directly maps to a Windows
function. The Windows function is indicating a lack of required memory
resources. Note that this error is returned by the operating system, so the
error number may change in future releases of Windows.

WSA_INVALID_PARAMETER

One
or more parameters are invalid.

An
application used a Windows Sockets function which directly maps to a Windows
function. The Windows function is indicating a problem with one or more
parameters. Note that this error is returned by the operating system, so the
error number may change in future releases of Windows.

WSA_OPERATION_ABORTED

995

Overlapped
operation aborted.

An
overlapped operation was canceled due to the closure of the socket, or the
execution of the SIO_FLUSH command in <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741621(v=vs.85).aspx»>WSAIoctl</a>.
Note that this error is returned by the operating system, so the error number
may change in future releases of Windows.

WSA_IO_INCOMPLETE

996

Overlapped
I/O event object not in signaled state.

The
application has tried to determine the status of an overlapped operation
which is not yet completed. Applications that use<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741582(v=vs.85).aspx»>WSAGetOverlappedResult</a> (with
the fWait flag set to FALSE) in a polling mode
to determine when an overlapped operation has completed, get this error code
until the operation is complete. Note that this error is returned by the
operating system, so the error number may change in future releases of
Windows.

WSA_IO_PENDING

997

Overlapped
operations will complete later.

The
application has initiated an overlapped operation that cannot be completed
immediately. A completion indication will be given later when the operation
has been completed. Note that this error is returned by the operating system,
so the error number may change in future releases of Windows.

WSAEINTR

10004

Interrupted
function call.

A
blocking operation was interrupted by a call to<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741547(v=vs.85).aspx»>WSACancelBlockingCall</a>.

WSAEBADF

10009

File
handle is not valid.

The
file handle supplied is not valid.

WSAEACCES

10013

Permission
denied.

An
attempt was made to access a socket in a way forbidden by its access
permissions. An example is using a broadcast address for <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740148(v=vs.85).aspx»>sendto</a> without
broadcast permission being set using <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a>(SO_BROADCAST).

Another
possible reason for the WSAEACCES error is that when the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737550(v=vs.85).aspx»>bind</a>function
is called (on Windows NT 4.0 with SP4 and later), another
application, service, or kernel mode driver is bound to the same address with
exclusive access. Such exclusive access is a new feature of
Windows NT 4.0 with SP4 and later, and is implemented by using the<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/cc150667(v=vs.85).aspx»>SO_EXCLUSIVEADDRUSE</a> option.

WSAEFAULT

10014

Bad
address.

The
system detected an invalid pointer address in attempting to use a pointer
argument of a call. This error occurs if an application passes an invalid
pointer value, or if the length of the buffer is too small. For instance, if
the length of an argument, which is a <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740496(v=vs.85).aspx»>sockaddr</a> structure,
is smaller than the sizeof(sockaddr).

WSAEINVAL

10022

Invalid
argument.

Some
invalid argument was supplied (for example, specifying an invalid level to
the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a> function).
In some instances, it also refers to the current state of the socket—for
instance, calling <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737526(v=vs.85).aspx»>accept</a> on
a socket that is not listening.

WSAEMFILE

10024

Too
many open files.

Too
many open sockets. Each implementation may have a maximum number of socket
handles available, either globally, per process, or per thread.

WSAEWOULDBLOCK

10035

Resource
temporarily unavailable.

This
error is returned from operations on nonblocking sockets that cannot be
completed immediately, for example <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740121(v=vs.85).aspx»>recv</a> when
no data is queued to be read from the socket. It is a nonfatal error, and the
operation should be retried later. It is normal for WSAEWOULDBLOCK to be
reported as the result from calling <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737625(v=vs.85).aspx»>connect</a> on
a nonblocking SOCK_STREAM socket, since some time must elapse for the
connection to be established.

WSAEINPROGRESS

10036

Operation
now in progress.

A
blocking operation is currently executing. Windows Sockets only allows a
single blocking operation—per- task or thread—to be outstanding, and if any
other function call is made (whether or not it references that or any other
socket) the function fails with the WSAEINPROGRESS error.

WSAEALREADY

10037

Operation
already in progress.

An
operation was attempted on a nonblocking socket with an operation already in
progress—that is, calling <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737625(v=vs.85).aspx»>connect</a> a
second time on a nonblocking socket that is already connecting, or canceling
an asynchronous request (WSAAsyncGetXbyY) that has already been
canceled or completed.

WSAENOTSOCK

10038

Socket
operation on nonsocket.

An
operation was attempted on something that is not a socket. Either the socket
handle parameter did not reference a valid socket, or for<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740141(v=vs.85).aspx»>select</a>,
a member of an fd_set was not valid.

WSAEDESTADDRREQ

10039

Destination
address required.

A
required address was omitted from an operation on a socket. For example, this
error is returned if <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740148(v=vs.85).aspx»>sendto</a> is
called with the remote address of ADDR_ANY.

WSAEMSGSIZE

10040

Message
too long.

A
message sent on a datagram socket was larger than the internal message buffer
or some other network limit, or the buffer used to receive a datagram was
smaller than the datagram itself.

WSAEPROTOTYPE

10041

Protocol
wrong type for socket.

A
protocol was specified in the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740506(v=vs.85).aspx»>socket</a> function
call that does not support the semantics of the socket type requested. For
example, the ARPA Internet UDP protocol cannot be specified with a socket
type of SOCK_STREAM.

WSAENOPROTOOPT

10042

Bad
protocol option.

An
unknown, invalid or unsupported option or level was specified in a<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms738544(v=vs.85).aspx»>getsockopt</a> or <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a> call.

WSAEPROTONOSUPPORT

10043

Protocol
not supported.

The
requested protocol has not been configured into the system, or no
implementation for it exists. For example, a <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740506(v=vs.85).aspx»>socket</a> call
requests a SOCK_DGRAM socket, but specifies a stream protocol.

WSAESOCKTNOSUPPORT

10044

Socket
type not supported.

The
support for the specified socket type does not exist in this address family.
For example, the optional type SOCK_RAW might be selected in a<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740506(v=vs.85).aspx»>socket</a> call,
and the implementation does not support SOCK_RAW sockets at all.

WSAEOPNOTSUPP

10045

Operation
not supported.

The
attempted operation is not supported for the type of object referenced.
Usually this occurs when a socket descriptor to a socket that cannot support
this operation is trying to accept a connection on a datagram socket.

WSAEPFNOSUPPORT

10046

Protocol
family not supported.

The
protocol family has not been configured into the system or no implementation
for it exists. This message has a slightly different meaning from
WSAEAFNOSUPPORT. However, it is interchangeable in most cases, and all
Windows Sockets functions that return one of these messages also specify
WSAEAFNOSUPPORT.

WSAEAFNOSUPPORT

10047

Address
family not supported by protocol family.

An
address incompatible with the requested protocol was used. All sockets are
created with an associated address family (that is, AF_INET for Internet
Protocols) and a generic protocol type (that is, SOCK_STREAM). This error is
returned if an incorrect protocol is explicitly requested in the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740506(v=vs.85).aspx»>socket</a> call,
or if an address of the wrong family is used for a socket, for example, in <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740148(v=vs.85).aspx»>sendto</a>.

WSAEADDRINUSE

10048

Address
already in use.

Typically,
only one usage of each socket address (protocol/IP address/port) is
permitted. This error occurs if an application attempts to<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737550(v=vs.85).aspx»>bind</a> a
socket to an IP address/port that has already been used for an existing
socket, or a socket that was not closed properly, or one that is still in the
process of closing. For server applications that need to bindmultiple
sockets to the same port number, consider using <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a>(SO_REUSEADDR).
Client applications usually need not call bind at all—<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737625(v=vs.85).aspx»>connect</a> chooses
an unused port automatically. When bind is called with a
wildcard address (involving ADDR_ANY), a WSAEADDRINUSE error could be delayed
until the specific address is committed. This could happen with a call to
another function later, including connect, <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms739168(v=vs.85).aspx»>listen</a>,<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741559(v=vs.85).aspx»>WSAConnect</a>,
or <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741628(v=vs.85).aspx»>WSAJoinLeaf</a>.

WSAEADDRNOTAVAIL

10049

Cannot
assign requested address.

The
requested address is not valid in its context. This normally results from an
attempt to <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737550(v=vs.85).aspx»>bind</a> to
an address that is not valid for the local computer. This can also result
from <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms737625(v=vs.85).aspx»>connect</a>, <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740148(v=vs.85).aspx»>sendto</a>, <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741559(v=vs.85).aspx»>WSAConnect</a>,<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741628(v=vs.85).aspx»>WSAJoinLeaf</a>,
or <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741693(v=vs.85).aspx»>WSASendTo</a> when
the remote address or port is not valid for a remote computer (for example,
address or port 0).

WSAENETDOWN

10050

Network
is down.

A
socket operation encountered a dead network. This could indicate a serious
failure of the network system (that is, the protocol stack that the Windows
Sockets DLL runs over), the network interface, or the local network itself.

WSAENETUNREACH

10051

Network
is unreachable.

A
socket operation was attempted to an unreachable network. This usually means
the local software knows no route to reach the remote host.

WSAENETRESET

10052

Network
dropped connection on reset.

The
connection has been broken due to keep-alive activity detecting a failure
while the operation was in progress. It can also be returned by<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a> if
an attempt is made to set <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ee470551(v=vs.85).aspx»>SO_KEEPALIVE</a> on
a connection that has already failed.

WSAECONNABORTED

10053

Software
caused connection abort.

An
established connection was aborted by the software in your host computer,
possibly due to a data transmission time-out or protocol error.

WSAECONNRESET

10054

Connection
reset by peer.

An
existing connection was forcibly closed by the remote host. This normally
results if the peer application on the remote host is suddenly stopped, the
host is rebooted, the host or remote network interface is disabled, or the
remote host uses a hard close (see <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a> for
more information on the SO_LINGER option on the remote socket). This error
may also result if a connection was broken due to keep-alive activity
detecting a failure while one or more operations are in progress. Operations
that were in progress fail with WSAENETRESET. Subsequent operations fail with
WSAECONNRESET.

WSAENOBUFS

10055

No
buffer space available.

An
operation on a socket could not be performed because the system lacked
sufficient buffer space or because a queue was full.

WSAEISCONN

10056

Socket
is already connected.

A
connect request was made on an already-connected socket. Some implementations
also return this error if <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740148(v=vs.85).aspx»>sendto</a> is
called on a connected SOCK_DGRAM socket (for SOCK_STREAM sockets, the to parameter
insendto is ignored) although other implementations treat this as
a legal occurrence.

WSAENOTCONN

10057

Socket
is not connected.

A
request to send or receive data was disallowed because the socket is not
connected and (when sending on a datagram socket using <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740148(v=vs.85).aspx»>sendto</a>)
no address was supplied. Any other type of operation might also return this
error—for example, <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740476(v=vs.85).aspx»>setsockopt</a> setting <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ee470551(v=vs.85).aspx»>SO_KEEPALIVE</a> if
the connection has been reset.

WSAESHUTDOWN

10058

Cannot
send after socket shutdown.

A
request to send or receive data was disallowed because the socket had already
been shut down in that direction with a previous <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740481(v=vs.85).aspx»>shutdown</a> call.
By calling shutdown a partial close of a socket is
requested, which is a signal that sending or receiving, or both have been
discontinued.

WSAETOOMANYREFS

10059

Too
many references.

Too
many references to some kernel object.

WSAETIMEDOUT

10060

Connection
timed out.

A
connection attempt failed because the connected party did not properly
respond after a period of time, or the established connection failed because
the connected host has failed to respond.

WSAECONNREFUSED

10061

Connection
refused.

No
connection could be made because the target computer actively refused it.
This usually results from trying to connect to a service that is inactive on
the foreign host—that is, one with no server application running.

WSAELOOP

10062

Cannot
translate name.

Cannot
translate a name.

WSAENAMETOOLONG

10063

Name
too long.

A
name component or a name was too long.

WSAEHOSTDOWN

10064

Host
is down.

A
socket operation failed because the destination host is down. A socket
operation encountered a dead host. Networking activity on the local host has
not been initiated. These conditions are more likely to be indicated by the
error WSAETIMEDOUT.

WSAEHOSTUNREACH

10065

No
route to host.

A
socket operation was attempted to an unreachable host. See WSAENETUNREACH.

WSAENOTEMPTY

10066

Directory
not empty.

Cannot
remove a directory that is not empty.

WSAEPROCLIM

10067

Too
many processes.

A
Windows Sockets implementation may have a limit on the number of applications
that can use it simultaneously. <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742213(v=vs.85).aspx»>WSAStartup</a> may
fail with this error if the limit has been reached.

WSAEUSERS

10068

User
quota exceeded.

Ran
out of user quota.

WSAEDQUOT

10069

Disk
quota exceeded.

Ran
out of disk quota.

WSAESTALE

10070

Stale
file handle reference.

The
file handle reference is no longer available.

WSAEREMOTE

10071

Item
is remote.

The
item is not available locally.

WSASYSNOTREADY

10091

Network
subsystem is unavailable.

This
error is returned by <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742213(v=vs.85).aspx»>WSAStartup</a> if
the Windows Sockets implementation cannot function at this time because the
underlying system it uses to provide network services is currently
unavailable. Users should check:

·
That the appropriate Windows Sockets DLL file is in the
current path.

·
That they are not trying to use more than one Windows Sockets
implementation simultaneously. If there is more than one Winsock DLL on your
system, be sure the first one in the path is appropriate for the network
subsystem currently loaded.

·
The Windows Sockets implementation documentation to be sure
all necessary components are currently installed and configured correctly.

WSAVERNOTSUPPORTED

10092

Winsock.dll
version out of range.

The
current Windows Sockets implementation does not support the Windows Sockets
specification version requested by the application. Check that no old Windows
Sockets DLL files are being accessed.

WSANOTINITIALISED

10093

Successful
WSAStartup not yet performed.

Either
the application has not called <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742213(v=vs.85).aspx»>WSAStartup</a> or WSAStartup failed.
The application may be accessing a socket that the current active task does
not own (that is, trying to share a socket between tasks), or<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741549(v=vs.85).aspx»>WSACleanup</a> has
been called too many times.

WSAEDISCON

10101

Graceful
shutdown in progress.

Returned
by <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741688(v=vs.85).aspx»>WSARecv</a> and <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741686(v=vs.85).aspx»>WSARecvFrom</a> to
indicate that the remote party has initiated a graceful shutdown sequence.

WSAENOMORE

10102

No
more results.

No
more results can be returned by the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741641(v=vs.85).aspx»>WSALookupServiceNext</a>function.

WSAECANCELLED

10103

Call
has been canceled.

A
call to the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741637(v=vs.85).aspx»>WSALookupServiceEnd</a> function
was made while this call was still processing. The call has been canceled.

WSAEINVALIDPROCTABLE

10104

Procedure
call table is invalid.

The
service provider procedure call table is invalid. A service provider returned
a bogus procedure table to Ws2_32.dll. This is usually caused by one or more
of the function pointers being NULL.

WSAEINVALIDPROVIDER

10105

Service
provider is invalid.

The
requested service provider is invalid. This error is returned by the<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742239(v=vs.85).aspx»>WSCGetProviderInfo</a> and <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742240(v=vs.85).aspx»>WSCGetProviderInfo32</a> functions
if the protocol entry specified could not be found. This error is also
returned if the service provider returned a version number other than 2.0.

WSAEPROVIDERFAILEDINIT

10106

Service
provider failed to initialize.

The
requested service provider could not be loaded or initialized. This error is
returned if either a service provider’s DLL could not be loaded (<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms684175(v=vs.85).aspx»>LoadLibrary</a> failed)
or the provider’s <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742296(v=vs.85).aspx»>WSPStartup</a> or <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms740047(v=vs.85).aspx»>NSPStartup</a>function
failed.

WSASYSCALLFAILURE

10107

System
call failure.

A
system call that should never fail has failed. This is a generic error code,
returned under various conditions.

Returned
when a system call that should never fail does fail. For example, if a call
to <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms742219(v=vs.85).aspx»>WaitForMultipleEvents</a> fails
or one of the registry functions fails trying to manipulate the
protocol/namespace catalogs.

Returned
when a provider does not return SUCCESS and does not provide an extended
error code. Can indicate a service provider implementation error.

WSASERVICE_NOT_FOUND

10108

Service
not found.

No
such service is known. The service cannot be found in the specified name
space.

WSATYPE_NOT_FOUND

10109

Class
type not found.

The
specified class was not found.

WSA_E_NO_MORE

10110

No
more results.

No
more results can be returned by the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741641(v=vs.85).aspx»>WSALookupServiceNext</a>function.

WSA_E_CANCELLED

10111

Call
was canceled.

WSAEREFUSED

10112

Database
query was refused.

A
database query failed because it was actively refused.

WSAHOST_NOT_FOUND

11001

Host
not found.

No
such host is known. The name is not an official host name or alias, or it
cannot be found in the database(s) being queried. This error may also be
returned for protocol and service queries, and means that the specified name
could not be found in the relevant database.

WSATRY_AGAIN

11002

Nonauthoritative
host not found.

This
is usually a temporary error during host name resolution and means that the
local server did not receive a response from an authoritative server. A retry
at some time later may be successful.

WSANO_RECOVERY

11003

This
is a nonrecoverable error.

This
indicates that some sort of nonrecoverable error occurred during a database
lookup. This may be because the database files (for example, BSD-compatible
HOSTS, SERVICES, or PROTOCOLS files) could not be found, or a DNS request was
returned by the server with a severe error.

WSANO_DATA

11004

Valid
name, no data record of requested type.

The
requested name is valid and was found in the database, but it does not have
the correct associated data being resolved for. The usual example for this is
a host name-to-address translation attempt (using<a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms738524(v=vs.85).aspx»>gethostbyname</a> or <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/ms741522(v=vs.85).aspx»>WSAAsyncGetHostByName</a>)
which uses the DNS (Domain Name Server). An MX record is returned but no A
record—indicating the host itself exists, but is not directly reachable.

WSA_QOS_RECEIVERS

11005

QoS
receivers.

At
least one QoS reserve has arrived.

WSA_QOS_SENDERS

11006

QoS
senders.

At
least one QoS send path has arrived.

WSA_QOS_NO_SENDERS

11007

No
QoS senders.

There
are no QoS senders.

WSA_QOS_NO_RECEIVERS

11008

QoS
no receivers.

There
are no QoS receivers.

WSA_QOS_REQUEST_CONFIRMED

11009

QoS
request confirmed.

The
QoS reserve request has been confirmed.

WSA_QOS_ADMISSION_FAILURE

11010

QoS
admission error.

A
QoS error occurred due to lack of resources.

WSA_QOS_POLICY_FAILURE

11011

QoS
policy failure.

The
QoS request was rejected because the policy system couldn’t allocate the
requested resource within the existing policy.

WSA_QOS_BAD_STYLE

11012

QoS
bad style.

An
unknown or conflicting QoS style was encountered.

WSA_QOS_BAD_OBJECT

11013

QoS
bad object.

A
problem was encountered with some part of the filterspec or the
provider-specific buffer in general.

WSA_QOS_TRAFFIC_CTRL_ERROR

11014

QoS
traffic control error.

An
error with the underlying traffic control (TC) API as the generic QoS request
was converted for local enforcement by the TC API. This could be due to an
out of memory error or to an internal QoS provider error.

WSA_QOS_GENERIC_ERROR

11015

QoS
generic error.

A
general QoS error.

WSA_QOS_ESERVICETYPE

11016

QoS
service type error.

An
invalid or unrecognized service type was found in the QoS flowspec.

WSA_QOS_EFLOWSPEC

11017

QoS
flowspec error.

An
invalid or inconsistent flowspec was found in the <a
href=»http://msdn.microsoft.com/en-us/library/windows/desktop/aa374024(v=vs.85).aspx»>QOS</a> structure.

WSA_QOS_EPROVSPECBUF

11018

Invalid
QoS provider buffer.

An
invalid QoS provider-specific buffer.

WSA_QOS_EFILTERSTYLE

11019

Invalid
QoS filter style.

An
invalid QoS filter style was used.

WSA_QOS_EFILTERTYPE

11020

Invalid
QoS filter type.

An
invalid QoS filter type was used.

WSA_QOS_EFILTERCOUNT

11021

Incorrect
QoS filter count.

An
incorrect number of QoS FILTERSPECs were specified in the FLOWDESCRIPTOR.

WSA_QOS_EOBJLENGTH

11022

Invalid
QoS object length.

An
object with an invalid ObjectLength field was specified in the QoS
provider-specific buffer.

WSA_QOS_EFLOWCOUNT

11023

Incorrect
QoS flow count.

An
incorrect number of flow descriptors was specified in the QoS structure.

WSA_QOS_EUNKOWNPSOBJ

11024

Unrecognized
QoS object.

An
unrecognized object was found in the QoS provider-specific buffer.

WSA_QOS_EPOLICYOBJ

11025

Invalid
QoS policy object.

An
invalid policy object was found in the QoS provider-specific buffer.

WSA_QOS_EFLOWDESC

11026

Invalid
QoS flow descriptor.

An
invalid QoS flow descriptor was found in the flow descriptor list.

WSA_QOS_EPSFLOWSPEC

11027

Invalid
QoS provider-specific flowspec.

An
invalid or inconsistent flowspec was found in the QoS provider-specific
buffer.

WSA_QOS_EPSFILTERSPEC

11028

Invalid
QoS provider-specific filterspec.

An
invalid FILTERSPEC was found in the QoS provider-specific buffer.

WSA_QOS_ESDMODEOBJ

11029

Invalid
QoS shape discard mode object.

An
invalid shape discard mode object was found in the QoS provider-specific
buffer.

WSA_QOS_ESHAPERATEOBJ

11030

Invalid
QoS shaping rate object.

An
invalid shaping rate object was found in the QoS provider-specific buffer.

WSA_QOS_RESERVED_PETYPE

11031

Reserved
policy QoS element type.

A
reserved policy element was found in the QoS provider-specific buffer.

Источник

WSAEACCES (10013)

Permission Denied.

An attempt was made to access a socket in a way forbidden by its access permissions. An example is using a broadcast address for sendto without broadcast permission being set using setsockopt(SO_BROADCAST).

Another possible reason for the WSAEACCES error is that when the bind function is called (on Windows NT 4 SP4 or later), another application, service, or kernel mode driver is bound to the same address with exclusive access. Such exclusive access is a new feature of Windows NT 4 SP4 and later, and is implemented by using the SO_EXCLUSIVEADDRUSE option.

WSAEADDRINUSE (10048)

Address already in use.

Only one usage of each socket address (protocol/IP address/port) is normally permitted. This error occurs if an application attempts to bind a socket to an IP address/port that has already been used for an existing socket, or a socket that wasn’t closed properly, or one that is still in the process of closing. For server applications that need to bind multiple sockets to the same port number, consider using setsockopt(SO_REUSEADDR). Client applications usually need not call bind at all — connect chooses an unused port automatically. When bind is called with a wildcard address (involving ADDR_ANY), a WSAEADDRINUSE error could be delayed until the specific address is committed. This could happen with a call to another function later, including connect, listen, WSAConnect or WSAJoinLeaf.

WSAEADDRNOTAVAIL (10049)

Cannot assign requested address.

The requested address is not valid in its context. This normally results from an attempt to bind to an address that is not valid for the local machine. This can also result from connect, sendto, WSAConnect, WSAJoinLeaf, or WSASendTo when the remote address or port is not valid for a remote machine (for example, address or port 0).

WSAEAFNOSUPPORT (10047)

Address family not supported by protocol family.

WSAEALREADY (10037)

Operation already in progress.

An operation was attempted on a nonblocking socket with an operation already in progress — that is, calling connect() a second time on a nonblocking socket that is already connecting, or canceling an asynchronous request (WSAAsyncGetXbyY) that has already been canceled or completed.

WSAECONNABORTED (10053)

Software caused connection abort.

An established connection was aborted by the software in your host machine, possibly due to a data transmission time-out or protocol error.

WSAECONNREFUSED (10061)

Connection refused.

No connection could be made because the target machine actively refused it. This usually results from trying to connect to a service that is inactive on the foreign host—that is, one with no server application running.

WSAECONNRESET (10054)

Connection reset by peer.

A existing connection was forcibly closed by the remote host. This normally results if the peer application on the remote host is suddenly stopped, the host is rebooted, or the remote host used a hard close (see setsockopt() for more information on the SO_LINGER option on the remote socket.) This error may also result if a connection was broken due to keepalive activity detecting a failure while one or more operations are in progress. Operations that were in progress fail with WSAENETRESET. Subsequent operations fail with WSAECONNRESET.

WSAEDESTADDRREQ (10039)

Destination address required.

A required address was omitted from an operation on a socket. For example, this error is returned if sendto is called with the remote address of ADDR_ANY.

WSAEFAULT (10014)

Bad address.

The system detected an invalid pointer address in attempting to use a pointer argument of a call. This error occurs if an application passes an invalid pointer value, or if the length of the buffer is too small. For instance, if the length of an argument which is a SOCKADDR structure is smaller than the sizeof(SOCKADDR).

WSAEHOSTDOWN (10064)

Host is down.

A socket operation failed because the destination host is down. A socket operation encountered a dead host. Networking activity on the local host has not been initiated. These conditions are more likely to be indicated by the error WSAETIMEDOUT.

WSAEHOSTUNREACH (10065)

No route to host.

A socket operation was attempted to an unreachable host. See WSAENETUNREACH

WSAEINPROGRESS (10036)

Operation now in progress.

A blocking operation is currently executing. Windows Sockets only allows a single blocking operation to be outstanding per task (or thread), and if any other function call is made (whether or not it references that or any other socket) the function fails with the WSAEINPROGRESS error.

WSAEINTR (10004)

Interrupted function call.

A blocking operation was interrupted by a call to WSACancelBlockingCall.

WSAEINVAL (10022)

Invalid argument.

Some invalid argument was supplied (for example, specifying an invalid level to the setsockopt function). In some instances, it also refers to the current state of the socket — for instance, calling accept on a socket that is not listening.

WSAEISCONN (10056)

Socket is already connected.

A connect request was made on an already connected socket. Some implementations also return this error if sendto is called on a connected SOCK_DGRAM socket (For SOCK_STREAM sockets, the to parameter in sendto is ignored), although other implementations treat this as a legal occurrence.

WSAEMFILE (10024)

Too many open files.

Too many open sockets. Each implementation may have a maximum number of socket handles available, either globally, per process, or per thread.

WSAEMSGSIZE (10040)

Message too long.

A message sent on a datagram socket was larger than the internal message buffer or some other network limit, or the buffer used to receive a datagram was smaller than the datagram itself.

WSAENETDOWN (10050)

Network is down.

A socket operation encountered a dead network. This could indicate a serious failure of the network system (that is, the protocol stack that the Windows Sockets .dll runs over), the network interface, or the local network itself.

WSAENETRESET (10052)

Network dropped connection on reset.

The connection has been broken due to keep-alive activity detecting a failure while the operation was in progress. It can also be returned by setsockopt if an attempt is made to set SO_KEEPALIVE on a connection that has already failed.

WSAENETUNREACH (10051)

Network is unreachable.

A socket operation was attempted to an unreachable network. This usually means the local software knows no route to reach the remote host.

WSAENOBUFS (10055)

No buffer space available.

An operation on a socket could not be performed because the system lacked sufficient buffer space or because a queue was full.

WSAENOPROTOOPT (10042)

Bad protocol option.

An unknown, invalid or unsupported option or level was specified in a getsockopt or setsockopt call.

WSAENOTCONN (10057)

Socket is not connected.

A request to send or receive data was disallowed because the socket is not connected and (when sending on a datagram socket using sendto) no address was supplied. Any other type of operation might also return this error � for example, setsockopt setting SO_KEEPALIVE if the connection has been reset.

WSAENOTSOCK (10038)

Socket operation on non-socket.

An operation was attempted on something that is not a socket. Either the socket handle parameter did not reference a valid socket, or for select, a member of an fd_set was not valid.

WSAEOPNOTSUPP (10045)

Operation not supported.

The attempted operation is not supported for the type of object referenced. Usually this occurs when a socket descriptor to a socket that cannot support this operation, for example, trying to accept a connection on a datagram socket.

WSAEPFNOSUPPORT (10046)

Protocol family not supported.

The protocol family has not been configured into the system or no implementation for it exists. Has a slightly different meaning to WSAEAFNOSUPPORT, but is interchangeable in most cases, and all Windows Sockets functions that return one of these specify WSAEAFNOSUPPORT.

WSAEPROCLIM (10067)

Too many processes.

A Windows Sockets implementation may have a limit on the number of applications that may use it simultaneously. WSAStartup may fail with this error if the limit has been reached.

WSAEPROTONOSUPPORT (10043)

Protocol not supported.

The requested protocol has not been configured into the system, or no implementation for it exists. For example, a socket call requests a SOCK_DGRAM socket, but specifies a stream protocol.

WSAEPROTOTYPE (10041)

Protocol wrong type for socket.

A protocol was specified in the socket function call that does not support the semantics of the socket type requested. For example, the ARPA Internet UDP protocol cannot be specified with a socket type of SOCK_STREAM.

WSAESHUTDOWN (10058)

Cannot send after socket shutdown.

A request to send or receive data was disallowed because the socket had already been shut down in that direction with a previous shutdown call. By calling shutdown a partial close of a socket is requested, which is a signal that sending or receiving or both have been discontinued.

WSAESOCKTNOSUPPORT (10044)

Socket type not supported.

The support for the specified socket type does not exist in this address family. For example, the optional type SOCK_RAW might be selected in a socket call, and the implementation does not support SOCK_RAW sockets at all.

WSAETIMEDOUT (10060)

Connection timed out.

A connection attempt failed because the connected party did not properly respond after a period of time, or the established connection failed because the connected host has failed to respond.

WSATYPE_NOT_FOUND (10109)

Class type not found.

The specified class was not found.

WSAEWOULDBLOCK (10035)

Resource temporarily unavailable.

This error is returned from operations on nonblocking sockets that cannot be completed immediately, for example recv when no data is queued to be read from the socket. It is a non-fatal error, and the operation should be retried later. It is normal for WSAEWOULDBLOCK to be reported as the result from calling connect on a nonblocking SOCK_STREAM socket, since some time must elapse for the connection to be established.

WSAHOST_NOT_FOUND (11001)

Host not found.

No such host is known. The name is not an official host name or alias, or it cannot be found in the database(s) being queried. This error may also be returned for protocol and service queries, and means the specified name could not be found in the relevant database.

WSA_INVALID_HANDLE (OS dependent)

Specified event object handle is invalid.

An application attempts to use an event object, but the specified handle is not valid.

WSA_INVALID_PARAMETER (OS dependent)

One or more parameters are invalid.

An application used a Windows Sockets function which directly maps to a Win32 function. The Win32 function is indicating a problem with one or more parameters.

WSAINVALIDPROCTABLE (OS dependent)

Invalid procedure table from service provider.

A service provider returned a bogus procedure table to WS2_32.dll. (Usually caused by one or more of the function pointers being NULL.)

WSAINVALIDPROVIDER (OS dependent)

Invalid service provider version number.

A service provider returned a version number other than 2.0.

WSA_IO_INCOMPLETE (OS dependent)

Overlapped I/O event object not in signaled state.

The application has tried to determine the status of an overlapped operation which is not yet completed. Applications that use WSAGetOverlappedResult (with the fWait flag set to FALSE) in a polling mode to determine when an overlapped operation has completed get this error code until the operation is complete.

WSA_IO_PENDING (OS dependent)

Overlapped operations will complete later.

The application has initiated an overlapped operation which cannot be completed immediately. A completion indication will be given at a later time when the operation has been completed.

WSA_NOT_ENOUGH_MEMORY (OS dependent)

Insufficient memory available.

An application used a Windows Sockets function which directly maps to a Win32 function. The Win32 function is indicating a lack of required memory resources.

WSANOTINITIALISED (10093)

Successful WSAStartup not yet performed.

Either the application hasn’t called WSAStartup or WSAStartup failed. The application may be accessing a socket which the current active task does not own (that is, trying to share a socket between tasks), or WSACleanup has been called too many times.

WSANO_DATA (11004)

Valid name, no data record of requested type.

The requested name is valid and was found in the database, but it does not have the correct associated data being resolved for. The usual example for this is a host name -> address translation attempt (using gethostbyname or WSAAsyncGetHostByName) which uses the DNS (Domain Name Server), and an MX record is returned but no A record — indicating the host itself exists, but is not directly reachable.

WSANO_RECOVERY (11003)

This is a non-recoverable error.

This indicates some sort of non-recoverable error occurred during a database lookup. This may be because the database files (for example, BSD-compatible HOSTS, SERVICES, or PROTOCOLS files) could not be found, or a DNS request was returned by the server with a severe error.

WSAPROVIDERFAILEDINIT (OS dependent)

Unable to initialize a service provider.

Either a service provider’s DLL could not be loaded (LoadLibrary failed) or the provider’s WSPStartup/NSPStartup function failed.

WSASYSCALLFAILURE (OS dependent)

System call failure.

Returned when a system call that should never fail does. For example, if a call to WaitForMultipleObjects fails or one of the registry functions fails trying to manipulate the protocol/name space catalogs.

WSASYSNOTREADY (10091)

Network subsystem is unavailable.

This error is returned by WSAStartup if the Windows Sockets implementation cannot function at this time because the underlying system it uses to provide network services is currently unavailable. Users should check:

That the appropriate Windows Sockets DLL file is in the current path.
That they are not trying to use more than one Windows Sockets implementation simultaneously. If there is more than one WINSOCK DLL on your system, be sure the first one in the path is appropriate for the network subsystem currently loaded.
The Windows Sockets implementation documentation to be sure all necessary components are currently installed and configured correctly.

WSATRY_AGAIN (11002)

Non-authoritative host not found.

This is usually a temporary error during host name resolution and means that the local server did not receive a response from an authoritative server. A retry at some time later may be successful.

WSAVERNOTSUPPORTED (10092)

WINSOCK.DLL version out of range.

The current Windows Sockets implementation does not support the Windows Sockets specification version requested by the application. Check that no old Windows Sockets .dll files are being accessed.

WSAEDISCON (10094)

Graceful shutdown in progress.

Returned by WSARecv and WSARecvFrom to indicate that the remote party has initiated a graceful shutdown sequence.

WSA_OPERATION_ABORTED (OS dependent)

Overlapped operation aborted.

An overlapped operation was canceled due to the closure of the socket, or the execution of the SIO_FLUSH command in WSAIoctl.

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From Microsoft’s Knowledge base:

WSAEACCES (10013)

Permission
denied.

An attempt was made to access a socket in a way forbidden by its
access permissions. An example is using a broadcast address for «sendto»
without broadcast permission being set using
setsockopt(SO_BROADCAST).

WSAEADDRINUSE (10048)

Address already
in use.

Only one usage of each socket address (protocol/IP address/port)
is normally permitted. This error occurs if an program attempts to bind a
socket to an IP address/port that has already been used for an existing socket,
or a socket that wasn’t closed properly, or one that is still in the process of
closing. For server programs that need to bind multiple sockets to the same
port number, consider using setsockopt(SO_REUSEADDR). Client programs usually
need not call bind at all — connect will choose an unused port
automatically.

WSAEADDRNOTAVAIL (10049)

Cannot assign requested
address.

The requested address is not valid in its context. Normally
results from an attempt to bind to an address that is not valid for the local
machine, or connect/sendto an address or port that is not valid for a remote
machine (e.g. port 0).

WSAEAFNOSUPPORT (10047)

Address family not
supported by protocol family.

An address incompatible with the requested
protocol was used. All sockets are created with an associated «address family»
(i.e. AF_INET for Internet Protocols) and a generic protocol type (i.e.
SOCK_STREAM). This error will be returned if an incorrect protocol is
explicitly requested in the socket call, or if an address of the wrong family
is used for a socket, e.g. in sendto.

WSAEALREADY
(10037)

Operation already in progress.

An operation was attempted
on a non-blocking socket that already had an operation in progress — i.e.
calling connect a second time on a non-blocking socket that is already
connecting, or canceling an asynchronous request (WSAAsyncGetXbyY) that has
already been canceled or completed.

WSAECONNABORTED
(10053)

Software caused connection abort.

An established
connection was aborted by the software in your host machine, possibly due to a
data transmission timeout or protocol error.

WSAECONNREFUSED
(10061)

Connection refused.

No connection could be made because
the target machine actively refused it. This usually results from trying to
connect to a service that is inactive on the foreign host — i.e. one with no
server program running.

WSAECONNRESET (10054)

Connection reset by
peer.

A existing connection was forcibly closed by the remote host. This
normally results if the peer program on the remote host is suddenly stopped,
the host is rebooted, or the remote host used a «hard close» (see setsockopt
for more information on the SO_LINGER option on the remote
socket.)

WSAEDESTADDRREQ (10039)

Destination address
required.

A required address was omitted from an operation on a socket.
For example, this error will be returned if sendto is called with the remote
address of ADDR_ANY.

WSAEFAULT (10014)

Bad address.

The
system detected an invalid pointer address in attempting to use a pointer
argument of a call. This error occurs if an program passes an invalid pointer
value, or if the length of the buffer is too small. For instance, if the length
of an argument which is a struct sockaddr is smaller than sizeof(struct
sockaddr).

WSAEHOSTDOWN (10064)

Host is down.

A socket
operation failed because the destination host was down. A socket operation
encountered a dead host. Networking activity on the local host has not been
initiated. These conditions are more likely to be indicated by the error
WSAETIMEDOUT.

WSAEHOSTUNREACH (10065)

No route to host.

A
socket operation was attempted to an unreachable host. See
WSAENETUNREACH

WSAEINPROGRESS (10036)

Operation now in
progress.

A blocking operation is currently executing. Windows Sockets
only allows a single blocking operation to be outstanding per task (or thread),
and if any other function call is made (whether or not it references that or
any other socket) the function fails with the WSAEINPROGRESS
error.

WSAEINTR (10004)

Interrupted function call.

A
blocking operation was interrupted by a call to
WSACancelBlockingCall.

WSAEINVAL (10022)

Invalid
argument.

Some invalid argument was supplied (for example, specifying an
invalid level to the setsockopt function). In some instances, it also refers to
the current state of the socket — for instance, calling accept on a socket that
is not listening.

WSAEISCONN (10056)

Socket is already
connected.

A connect request was made on an already connected socket.
Some implementations also return this error if sendto is called on a connected
SOCK_DGRAM socket (For SOCK_STREAM sockets, the to parameter in sendto is
ignored), although other implementations treat this as a legal
occurrence.

WSAEMFILE (10024)

Too many open files.

Too
many open sockets. Each implementation may have a maximum number of socket
handles available, either globally, per process or per
thread.

WSAEMSGSIZE (10040)

Message too long.

A message
sent on a datagram socket was larger than the internal message buffer or some
other network limit, or the buffer used to receive a datagram into was smaller
than the datagram itself.

WSAENETDOWN (10050)

Network is
down.

A socket operation encountered a dead network. This could indicate
a serious failure of the network system (the protocol stack that the WinSock
DLL runs over), the network interface, or the local network
itself.

WSAENETRESET (10052)

Network dropped connection on
reset.

The host you were connected to crashed and rebooted. May also be
returned by setsockopt if an attempt is made to set SO_KEEPALIVE on a
connection that has already failed.

WSAENETUNREACH
(10051)

Network is unreachable.

A socket operation was attempted
to an unreachable network. This usually means the local software knows no route
to reach the remote host.

WSAENOBUFS (10055)

No buffer space
available.

An operation on a socket could not be performed because the
system lacked sufficient buffer space or because a queue was
full.

WSAENOPROTOOPT (10042)

Bad protocol option.

An
unknown, invalid or unsupported option or level was specified in a getsockopt
or setsockopt call.

WSAENOTCONN (10057)

Socket is not
connected.

A request to send or receive data was disallowed because the
socket is not connected and (when sending on a datagram socket using sendto) no
address was supplied. Any other type of operation might also return this error
— for example, setsockopt setting SO_KEEPALIVE if the connection has been
reset.

WSAENOTSOCK (10038)

Socket operation on
non-socket.

An operation was attempted on something that is not a
socket. Either the socket handle parameter did not reference a valid socket, or
for select, a member of an fd_set was not valid.

WSAEOPNOTSUPP
(10045)

Operation not supported.

The attempted operation is not
supported for the type of object referenced. Usually this occurs when a socket
descriptor to a socket that cannot support this operation, for example, trying
to accept a connection on a datagram socket.

WSAEPFNOSUPPORT
(10046)

Protocol family not supported.

The protocol family has
not been configured into the system or no implementation for it exists. Has a
slightly different meaning to WSAEAFNOSUPPORT, but is interchangeable in most
cases, and all Windows Sockets functions that return one of these specify
WSAEAFNOSUPPORT.

WSAEPROCLIM (10067)

Too many processes.

A
Windows Sockets implementation may have a limit on the number of programs that
may use it simultaneously. WSAStartup may fail with this error if the limit has
been reached.

WSAEPROTONOSUPPORT (10043)

Protocol not
supported.

The requested protocol has not been configured into the
system, or no implementation for it exists. For example, a socket call requests
a SOCK_DGRAM socket, but specifies a stream protocol.

WSAEPROTOTYPE
(10041)

Protocol wrong type for socket.

A protocol was specified
in the socket function call that does not support the semantics of the socket
type requested. For example, the ARPA Internet UDP protocol cannot be specified
with a socket type of SOCK_STREAM.

WSAESHUTDOWN (10058)

Cannot
send after socket shutdown.

A request to send or receive data was
disallowed because the socket had already been shut down in that direction with
a previous shutdown call. By calling shutdown a partial close of a socket is
requested, which is a signal that sending or receiving or both has been
discontinued.

WSAESOCKTNOSUPPORT (10044)

Socket type not
supported.

The support for the specified socket type does not exist in
this address family. For example, the optional type SOCK_RAW might be selected
in a socket call, and the implementation does not support SOCK_RAW sockets at
all.

WSAETIMEDOUT (10060)

Connection timed out.

A
connection attempt failed because the connected party did not properly respond
after a period of time, or established connection failed because connected host
has failed to respond.

WSAEWOULDBLOCK (10035)

Resource
temporarily unavailable.

This error is returned from operations on
non-blocking sockets that cannot be completed immediately, for example recv
when no data is queued to be read from the socket. It is a non-fatal error, and
the operation should be retried later. It is normal for WSAEWOULDBLOCK to be
reported as the result from calling connect on a non-blocking SOCK_STREAM
socket, since some time must elapse for the connection to be
established.

WSAHOST_NOT_FOUND (11001)

Host not found.

No
such host is known. The name is not an official hostname or alias, or it cannot
be found in the database(s) being queried. This error may also be returned for
protocol and service queries, and means the specified name could not be found
in the relevant database.

WSA_INVALID_HANDLE (OS
dependent)

Specified event object handle is invalid.

An program
attempts to use an event object, but the specified handle is not
valid.

WSA_INVALID_PARAMETER (OS dependent)

One or more
parameters are invalid.

An program used a Windows Sockets function which
directly maps to a Win32 function. The Win32 function is indicating a problem
with one or more parameters.

WSAINVALIDPROCTABLE (OS
dependent)

Invalid procedure table from service provider.

A
service provider returned a bogus proc table to WS2_32.DLL. (Usually caused by
one or more of the function pointers being NULL.)

WSAINVALIDPROVIDER (OS
dependent)

Invalid service provider version number.

A service
provider returned a version number other than 2.0.

WSA_IO_PENDING (OS
dependent)

Overlapped operations will complete later.

The program
has initiated an overlapped operation which cannot be completed immediately. A
completion indication will be given at a later time when the operation has been
completed.

WSA_IO_INCOMPLETE (OS dependent)

Overlapped I/O event
object not in signaled state.

The program has tried to determine the
status of an overlapped operation which is not yet completed. Programs that use
WSAWaitForMultipleEvents in a polling mode to determine when an overlapped
operation has completed will get this error code until the operation is
complete.

WSA_NOT_ENOUGH_MEMORY (OS dependent)

Insufficient
memory available.

An program used a Windows Sockets function which
directly maps to a Win32 function. The Win32 function is indicating a lack of
required memory resources.

WSANOTINITIALISED (10093)

Successful
WSAStartup not yet performed.

Either the program has not called
WSAStartup or WSAStartup failed. The program may be accessing a socket which
the current active task does not own (i.e. trying to share a socket between
tasks), or WSACleanup has been called too many times.

WSANO_DATA
(11004)

Valid name, no data record of requested type.

The
requested name is valid and was found in the database, but it does not have the
correct associated data being resolved for. The usual example for this is a
hostname -> address translation attempt (using gethostbyname or
WSAAsyncGetHostByName) which uses the DNS (Domain Name Server), and an MX
record is returned but no A record — indicating the host itself exists, but is
not directly reachable.

WSANO_RECOVERY (11003)

This is a
non-recoverable error.

This indicates some sort of non-recoverable error
occurred during a database lookup. This may be because the database files (e.g.
BSD-compatible HOSTS, SERVICES or PROTOCOLS files) could not be found, or a DNS
request was returned by the server with a severe
error.

WSAPROVIDERFAILEDINIT (OS dependent)

Unable to initialize
a service provider.

Either a service provider’s DLL could not be loaded
(LoadLibrary failed) or the provider’s WSPStartup/NSPStartup function
failed.

WSASYSCALLFAILURE (OS dependent)

System call
failure.

Returned when a system call that should never fail does. For
example, if a call to WaitForMultipleObjects fails or one of the registry
functions fails trying to manipulate theprotocol/namespace
catalogs.

WSASYSNOTREADY (10091)

Network subsystem is
unavailable.

This error is returned by WSAStartup if the Windows Sockets
implementation cannot function at this time because the underlying system it
uses to provide network services is currently unavailable. Users should check:

That the appropriate Windows Sockets DLL file is in the current
path.

That they are not trying to use more than one Windows Sockets
implementation simultaneously. If there is more than one WINSOCK DLL on your
system, be sure the first one in the path is appropriate for the network
subsystem currently loaded.

That the Windows Sockets implementation
documentation to be sure all necessary components are currently installed and
configured correctly.

WSATRY_AGAIN (11002)

Non-authoritative
host not found.

This is usually a temporary error during hostname
resolution and means that the local server did not receive a response from an
authoritative server. A retry at some time later may be
successful.

WSAVERNOTSUPPORTED (10092)

WINSOCK.DLL version out of
range.

The current Windows Sockets implementation does not support the
Windows Sockets specification version requested by the program. Check that no
old Windows Sockets DLL files are being accessed.

WSAEDISCON
(10094)

Graceful shutdown in progress.

Returned by recv, WSARecv
to indicate the remote party has initiated a graceful shutdown
sequence.

WSA_OPERATION_ABORTED (OS dependent)

Overlapped
operation aborted.

An overlapped operation was canceled due to the
closure of the socket, or the execution of the SIO_FLUSH command in WSAIoctl.

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