Bash throw error

raise Some_Error;

raise Some_Error with "Out of memory"; -- specific diagnostic message

with Ada.Exceptions, Ada.Text_IO;

procedure Foo is
  Some_Error : exception;
begin
  Do_Something_Interesting;
exception -- Start of exception handlers
  when Constraint_Error =>
    ... -- Handle constraint error
  when Storage_Error =>
    -- Propagate Storage_Error as a different exception with a useful message
    raise Some_Error with "Out of memory";
  when Error : others => 
    -- Handle all others
    Ada.Text_IO.Put("Exception: ");
    Ada.Text_IO.Put_Line(Ada.Exceptions.Exception_Name(Error));
    Ada.Text_IO.Put_Line(Ada.Exceptions.Exception_Message(Error));
end Foo;

#!/usr/bin/env bash
#set -e provides another error mechanism
print_error(){
	echo "there was an error"
}
trap print_error exit #list signals to trap
tempfile=`mktemp`
trap "rm $tempfile" exit
./other.sh || echo warning: other failed
echo oops)
echo never printed

ON ERROR GOTO handler
OPEN "Somefile.txt" FOR INPUT AS #1
CLOSE #1
PRINT "File opened successfully"
END

handler:
PRINT "File does not exist"
END  ' RESUME may be used instead which returns control to original position.

#include <setjmp.h>
#include <stdio.h>
#include <stdlib.h>

enum { SOME_EXCEPTION = 1 } exception;
jmp_buf state;

int main(void)
{
  if (!setjmp(state))                      // try
  {
    if (/* something happened */)
    {
      exception = SOME_EXCEPTION;
      longjmp(state, 0);                  // throw SOME_EXCEPTION
    }
  } 
  else switch(exception)
  {             
    case SOME_EXCEPTION:                  // catch SOME_EXCEPTION
      puts("SOME_EXCEPTION caught");
      break;
    default:                              // catch ...
      puts("Some strange exception");
  }
  return EXIT_SUCCESS;
}

int filterExpression (EXCEPTION_POINTERS* ep) {
   ep->ContextRecord->Eip += 8; // divide instruction may be encoded from 2 to 8 bytes
   return EXCEPTION_CONTINUE_EXECUTION;
}
int main(void) {
   static int zero;
   __try {
       zero = 1/zero;
       __asm {
         nop
         nop
         nop
         nop
         nop
         nop
         nop
       }
       printf ("Past the exception.n");
   } __except (filterExpression (GetExceptionInformation())) {
       printf ("Handler called.n");
   }
   return 0;
}

public static void Main()
{
    try
    {
        // Code that could throw an exception.
    }
    catch (HttpException ex)
    {
        // Handles a HttpException. The exception object is stored in "ex".
    }
    catch (Exception)
    {
        // Handles any CLR exception that is not a HttpException.
        // Since the exception has not been given an identifier, it cannot be referenced.
    }
    catch
    {
        // Handles anything that might be thrown, including non-CLR exceptions.
    }
    finally
    {
        // Always run when leaving the try block (including catch clauses), regardless of whether any exceptions were thrown or whether they were handled.
        // Often used to clean up and close resources such a file handles.
        // May not be run when Environment.FailFast() is called and in other system-wide exceptional conditions (e.g. power loss), or when the process crashes due to an exception in another thread.
    }
}

#include <exception>
int main() {
   try {
       // do something (might throw an exception)
   }
   catch (const std::exception& e) {
        // handle exception e
   }
   catch (...) {
        // catches all exceptions, not already caught by a catch block before
        // can be used to catch exception of unknown or irrelevant type
   }
}

<cfscript>
try {
	//throw CF9+
	throw(type="TypeOfException", message="Oops", detail="xyz");
	// alternate throw syntax:
	throw "Oops"; // this equivalent to the "message" value in the above example
} catch (any e) {
	writeOutput("Error: " & e.message);
	rethrow; //CF9+
} finally { //CF9+
	writeOutput("I run even if no error");
}
</cfscript>

<cftry> 
    code that may cause an exception 
    <cfcatch ...> 
        <cftry> 
            First level of exception handling code 
            <cfcatch ...> 
                Second level of exception handling code 
            </cfcatch>
            <cffinally> 
                    final code    
             </cffinally> 
        </cftry> 
    </cfcatch> 
</cftry>

try {
	// code which could result in an exception

} catch (any e){
	retry;
}

<cftry>

	<!--- code which could result in an exception --->

	<cfcatch>
		<cfretry>
	</cfcatch>
</cftry>

import std.stdio; // for writefln()
int main() {
  try {
      // do something that might throw an exception
  }
  catch (FooException e) {
       // handle exceptions of type FooException
  }
  catch (Object o) {
       // handle any other exceptions
       writefln("Unhandled exception: ", o);
       return 1;
  }
  return 0;
}

type ECustom = class(Exception) // Exceptions are children of the class Exception.
  private
    FCustomData: SomeType;      // Exceptions may have custom extensions.
  public
    constructor CreateCustom(Data: SomeType); // Needs an implementation
    property CustomData: SomeType read FCustomData;
  end;

raise Exception.Create('Message');

raise Exception.CreateFmt('Message with values: %d, %d',[value1, value2]); // See SysUtils.Format() for parameters.

raise ECustom.CreateCustom(X);

try // For finally.
  try // For except.
    ... // Code that may raise an exception.
  except
    on C:ECustom do
      begin
        ... // Handle ECustom.
        ... if Predicate(C.CustomData) then ...
      end;
    on S:ESomeOtherException do
      begin
        // Propagate as an other exception.
        raise EYetAnotherException.Create(S.Message); 
      end;
    on E:Exception do
      begin
        ... // Handle other exceptions.
        raise; // Propagate.
      end;
  end; 
finally
  // Code to execute whether or not an exception is raised (e.g., clean-up code).
end;

try
  % some dangerous code
catch
  throw:{someError, X} -> ok;    % handle an exception
  error:X -> ok;                 % handle another exception
  _:_ -> ok                      % handle all exceptions
after
  % clean up
end

try
    try
        () (* Code that could throw an exception. *)
    with
    | :? System.Net.WebException as ex -> () (* Handles a WebException. The exception object is stored in "ex". *)
    | :? exn -> () (* Handles any CLR exception. Since the exception has not been given an identifier, it cannot be referenced. *)
    | _ -> () (* Handles anything that might be thrown, including non-CLR exceptions. *)
finally
    () 
    (*
       Always run when leaving the try block, regardless of whether any exceptions were thrown or whether they were handled.
       Often used to clean up and close resources such a file handles.
       May not be run when Environment.FailFast() is called and in other system-wide exceptional conditions (e.g. power loss), or when the process crashes due to an exception in another thread.
    *)

exception MyException of string * int (* exceptions can carry a value *)
let _ =
  try
    raise (MyException ("not enough food", 2));
    printfn "Not reached"
  with
  | MyException (s, i) -> 
      printf "MyException: %s, %dn" s i
  | e ->  (* catch all exceptions *)
     eprintf "Unexpected exception : %O" e;
     eprintf "%O" e.StackTrace

import Prelude hiding(catch)
import Control.Exception
instance Exception Int
instance Exception Double
main = do
  catch
    (catch
      (throw (42::Int))
      (e-> print (0,e::Double)))
    (e-> print (1,e::Int))

#include <iostream>
using namespace std;
int main()
{
  try
    {throw (int)42;}
  catch(double e)
    {cout << "(0," << e << ")" << endl;}
  catch(int e)
    {cout << "(1," << e << ")" << endl;}
}

do {
  -- Statements in which errors might be thrown
} `catch` ex -> do {
  -- Statements that execute in the event of an exception, with 'ex' bound to the exception
}

try {
    // Normal execution path.
    throw new EmptyStackException();
} catch (ExampleException ee) {
    // Deal with the ExampleException.
} finally {
    // Always run when leaving the try block (including finally clauses), regardless of whether any exceptions were thrown or whether they were handled.
    // Often used to clean up and close resources such a file handles.
    // May not be run when System.exit() is called and in other system-wide exceptional conditions (e.g. power loss).
}

try {
  // Statements in which exceptions might be thrown
  throw new Error("error");
} catch(error) {
  // Statements that execute in the event of an exception
} finally {
  // Statements that execute afterward either way
}

setInterval(function() {
  throw new Error("Example of an error thrown on a 4 second interval.");
}, 4000);

try {
  throw 12345; // primitive number
} catch(error) {
  console.log(error); // logs 12345 as a primitive number to the console
}

// Example in Java
try {
  Integer i = null;
  i.intValue(); // throws a NullPointerException
} catch(NullPointerException error) {
  // Variable might be null
} catch(ArithmeticException error) {
  // Handle problems with numbers
}

// Approximation #1 in JavaScript
try {
  // Statements in which exceptions might be thrown
  var example = null;
  example.toString();
} catch(error) {
  if (error.type === "TypeError") {
    // Variable might be null
  } else if (error.type === "RangeError") {
    // Handle problems with numbers
  }
}

// Approximation #2 in JavaScript
try {
  try {
    // Statements in which exceptions might be thrown
    var example = null;
    example.toString();
  } catch(error) {
    if (error.type !== "TypeError") throw error;
    // Variable might be null
  }
} catch(error) {
  if (error.type !== "RangeError") throw error;
  // Handle problems with numbers
}

new Promise(function() {
	throw new Error("Example error!");
}).catch(function(err) {
	console.log("Caught ", err);
});

addEventListener("unhandledrejection", function(event) {
  console.log(event.reason);
  event.preventDefault(); //prevent logging the error via console.error to the console--the default behavior
});

new Promise(function() {
  throw new Error("Example error!");
});

try {
  // Statements in which exceptions might be thrown
  const obj = {};
  obj.selfPropExample = obj; // circular reference
  throw obj;
} catch(error) {
  // Statements that execute in the event of an exception
}

(ignore-errors (/ 1 0))

(handler-case
    (progn
      (print "enter an expression")
      (eval (read)))
  (error (e) (print e)))

(unwind-protect
    (progn
       (print "enter an expression")
       (eval (read)))
  (print "This print will always be executed, similar to finally."))

function foo(x)
  if x then 
    return x
  else
    error "Not a true value"
  end
end

function attempt(arg)
  success, value = pcall(foo, arg)

  if not success then 
    print("Error: " .. tostring(value))
  else
    print("Returned: " .. tostring(value))
  end
end

attempt("hello")
  -- Returned: hello

attempt(nil)
  -- Error: stdin:5: Not a true value

attempt({})
  -- Returned: table: 00809308
    
if foo(42) then print "Success" end
  -- Success

if pcall(
  function()
    -- Do something that might throw an error.
  end) 
then
  print "No errors"  -- Executed if the protected call was successful.
else
  print "Error encountered"  -- Executed if the protected call failed.
end

print "Done"  -- Will always be executed

throw MyError("this happened")

try {
  # something
} catch(e:MyError) {
  guard e.val = 7
  # ...
} catch(e:MyError) {
  # ...
} catch(e:Error) {
  # ...
}

try 1/0  # evaluates to null

1/0 tor 20  # evaluates to 20

my_result = block my_block {  # "block" catches exception thrown by return below
  # do calculation
  if calculation_finished() {
    my_block.return(42)  # throws exception
  }
}

NSException *exception = [NSException exceptionWithName:@"myException"
                           reason:@"yourReason"  userInfo:nil];

@try {
    ...
}
@catch (SomeException *se) {
    // Handle a specific exception type.
    ...
}
@catch (NSException *ne) {
    // Handle general exceptions.
    ...

    // Propagate the exception so that it's handled at a higher level.
    @throw;
}
@catch (id ue) {
    // Catch all thrown objects.
    ...
}
@finally {
    // Perform cleanup, whether an exception occurred or not.
    ...
}

exception MyException of string * int (* exceptions can carry a value *)
let _ =
  try
    raise (MyException ("not enough food", 2));
    print_endline "Not reached"
  with
  | MyException (s, i) -> 
      Printf.printf "MyException: %s, %dn" s i
  | e ->  (* catch all exceptions *)
     Printf.eprintf "Unexpected exception : %s" (Printexc.to_string e);
     (*If using Ocaml >= 3.11, it is possible to also print a backtrace: *)
     Printexc.print_backtrace stderr;
       (* Needs to beforehand enable backtrace recording with
           Printexc.record_backtrace true
         or by setting the environment variable OCAMLRUNPARAM="b1"*)

eval {
    open(FILE, $file) || die MyException::File->new($!);
    while (<FILE>) {
        process_line($_);
    }
    close(FILE) || die MyException::File->new($!);
};
if ($@) {
    # The exception object is in $@
    if ($@->isa('MyException::File')) {
        # Handle file exception
    } else {
        # Generic exception handling
        # or re-throw with 'die $@'
    }
}

local $SIG{__DIE__} = sub {
    my $err = shift;
    if ($err->isa('MyException')) {
        die $err; # re-throw
    } else {
        # Otherwise construct a MyException with $err as a string
        die MyException::Default->new($err);
    }
};

eval {
    # Code that could throw an exception (using 'die') but does NOT use the return statement;
    1;
} or do {
    # Handle exception here. The exception string is in $@
};

// Exception handling is only available in PHP versions 5 and greater.
try {
    // Code that might throw an exception
    throw new Exception('Invalid URL.');
} catch (FirstExceptionClass $exception) {
    // Code that handles this exception
} catch (SecondExceptionClass $exception) {
    // Code that handles a different exception
} finally {
    // Perform cleanup, whether an exception occurred or not.
}

trap [Exception]
{
    # Statements that execute in the event of an exception
}
# Statements in which exceptions might be thrown

Try {
    Import-Module ActiveDirectory
    }
Catch [Exception1] {
  # Statements that execute in the event of an exception, matching the exception
    }
Catch [Exception2],[Exception3etc] {
  # Statements that execute in the event of an exception, matching any of the exceptions
    }
Catch {
  # Statements that execute in the event of an exception, not handled more specifically
    }

f = None
try:
    f = open("aFileName", "w")
    f.write(could_make_error())
except IOError:
    print("Unable to open file")
except:  # catch all exceptions
    print("Unexpected error")
else:  # executed if no exceptions are raised
    print("File write completed successfully")
finally:  # clean-up actions, always executed
    if f:
        f.close()

tryCatch({
   stop("Here an error is signaled")   # default S3-class is simpleError a subclass of error
   cat("This and the following lines are not executed because the error is trapped beforen")
   stop( structure(simpleError("mySpecialError message"),class=c("specialError","error","condition")) )
}
,specialError=function(e){
    cat("catches errors of class specialErrorn")
}
,error=function(e){
    cat("catches the default errorn")
}
,finally={ cat("do some cleanup (e.g., setwd)n") }
)

REBOL [
    Title: "Exception and error handling examples"
]

; TRY a block; capturing an error! and converting to object!
if error? exception: try [1 / 0][probe disarm exception]

; ATTEMPT results in the value of the block or the value none on error
print attempt [divide 1 0]

; User generated exceptions can be any datatype!
example: func ["A function to throw an exception"
][
    throw "I'm a string! exception"
]
catch [example]

; User generated exceptions can also be named,
;   and functions can include additional run time attributes 
sophisticated: func ["A function to throw a named error exception"
    [catch]
][
    throw/name make error! "I'm an error! exception" 'moniker
]
catch/name [sophisticated] 'moniker

 signal on halt;
 do a = 1
	 say a
	 do 100000 /* a delay */
	 end
 end
 halt:
 say "The program was stopped by the user"
 exit

begin
  # Do something nifty
  raise SomeError, "This is the error message!"  # Uh-oh!
rescue SomeError
  # This is executed when a SomeError exception
  # is raised
rescue AnotherError => error
  # Here, the exception object is referenced from the
  # `error' variable
rescue
  # This catches all exceptions derived from StandardError
  retry # This executes the begin section again
else
  # This is executed only if no exceptions were raised
ensure
  # This is always executed, exception or not
end

  [ "code that might throw an exception" ]
     on: ExceptionClass 
     do: [:ex | "code that handles exception" ].

enum MyException : ErrorType {
  case Foo(String, Int)
}
func someFunc() throws {
  throw MyException.Foo("not enough food", 2)
}
do {
  try someFunc()
  print("Not reached")
} catch MyException.Foo(let s, let i) {
  print("MyException: (s), (i)")
} catch {
  print("Unexpected exception : (error)")
}

if { [ catch {
    foo
} err ] } {
    puts "Error: $err"
}

try {
    someCommandWithExceptions
} on ok {res opt} {
    # handle normal case.
} trap ListPattern1 {err opt} {
    # handle exceptions with an errorcode matching ListPattern1
} trap ListPattern2 {err opt} {
    # ...
} on error {err opt} {
    # handle everything else.
} finally {
    # run whatever commands must run after the try-block.
}

With New Try: On Error Resume Next
    'do Something (only one statement recommended)
.Catch: On Error GoTo 0: Select Case .Number
    Case 0 'this line is required when using 'Case Else' clause because of the lack of "Is" keyword in VBScript Case statement
        'no exception
    Case SOME_ERRORNUMBER
        'exception handling
    Case Else
        'unknown exception
End Select: End With

' *** Try Class ***
Class Try
    Private mstrDescription
    Private mlngHelpContext
    Private mstrHelpFile
    Private mlngNumber
    Private mstrSource

    Public Sub Catch()
        mstrDescription = Err.Description
        mlngHelpContext = Err.HelpContext
        mstrHelpFile = Err.HelpFile
        mlngNumber = Err.Number
        mstrSource = Err.Source
    End Sub

    Public Property Get Source()
        Source = mstrSource
    End Property
    
    Public Property Get Number()
        Number = mlngNumber
    End Property

    Public Property Get HelpFile()
        HelpFile = mstrHelpFile
    End Property
    
    Public Property Get HelpContext()
        HelpContext = mlngHelpContext
    End Property
    
    Public Property Get Description()
        Description = mstrDescription
    End Property
End Class

On Error GoTo HandlerLabel 'When error has occurred jumps to HandlerLabel, which is defined anywhere within Function or Sub
'or
On Error GoTo 0 'switch off error handling. Error causes fatal runtime error and stops application
'or
On Error Resume Next 'Object Err is set, but execution continues on next command. You can still use Err object to check error state.
'...
Err.Raise 6   ' Generate an "Overflow" error using build-in object Err. If there is no error handler, calling procedure can catch exception by same syntax
'...

FinallyLabel: 'just common label within procedure (non official emulation of Finally section from other languages)
    'cleanup code, always executed
Exit Sub 'exits procedure

'because we are after Exit Sub statement, next code is hidden for non-error execution
HandlerLabel: 'defines a common label, here used for exception handling.
If Err.Number = 6 Then 'Select Case statement is typically better solution
    Resume FinallyLabel 'continue execution on specific label. Typically something with meaning of "Finally" in other languages
    'or
    Resume Next 'continue execution on statement next to "Err.Raise 6"
    'or
    Resume 'continue execution on (repeat) statement "Err.Raise 6"
End If

MsgBox Err.Number & " " & Err.Source & " " & Erl & " " & Err.Description & " " & Err.LastDllError 'show message box with important error properties
    'Erl is VB6 build-in line number global variable (if used). Typically is used some kind of IDE Add-In, which labels every code line with number before compilation
Resume FinallyLabel

With New Try: On Error Resume Next 'Create new object of class "Try" and use it. Then set this object as default. Can be "Dim T As New Try: ... ... T.Catch
    'do Something (only one statement recommended)
.Catch: On Error GoTo 0: Select Case .Number 'Call Try.Catch() procedure. Then switch off error handling. Then use "switch-like" statement on result of Try.Number property (value of property Err.Number of build-in Err object)
    Case SOME_ERRORNUMBER
        'exception handling
    Case Is <> 0 'When Err.Number is zero, no error has occurred
        'unknown exception
End Select: End With

' *** Try Class ***
Private mstrDescription  As String
Private mlngHelpContext  As Long
Private mstrHelpFile     As String
Private mlngLastDllError As Long
Private mlngNumber       As Long
Private mstrSource       As String

Public Sub Catch()
    mstrDescription = Err.Description
    mlngHelpContext = Err.HelpContext
    mstrHelpFile = Err.HelpFile
    mlngLastDllError = Err.LastDllError
    mlngNumber = Err.Number
    mstrSource = Err.Source
End Sub

Public Property Get Source() As String
    Source = mstrSource
End Property

Public Property Get Number() As Long
    Number = mlngNumber
End Property

Public Property Get LastDllError() As Long
    LastDllError = mlngLastDllError
End Property

Public Property Get HelpFile() As String
    HelpFile = mstrHelpFile
End Property

Public Property Get HelpContext() As Long
    HelpContext = mlngHelpContext
End Property

Public Property Get Description() As String
    Description = mstrDescription
End Property

Try
   ' code to be executed here
Catch ex As Exception When condition
   ' Handle Exception when a specific condition is true. The exception object is stored in "ex".
Catch ex As ExceptionType
   ' Handle Exception of a specified type (i.e. DivideByZeroException, OverflowException, etc.)
Catch ex As Exception
   ' Handle Exception (catch all exceptions of a type not previously specified)
Catch
   ' Handles anything that might be thrown, including non-CLR exceptions.
Finally
   ' Always run when leaving the try block (including catch clauses), regardless of whether any exceptions were thrown or whether they were handled.
   ' Often used to clean up and close resources such a file handles.
   ' May not be run when Environment.FailFast() is called and in other system-wide exceptional conditions (e.g. power loss), or when the process crashes due to an exception in another thread.
End Try

try
    % Block to protect
catch TraceId do
    % Code to execute in the event of an exception; TraceId gives access to the exception information
finally
    % Code will be executed regardles however the other parts behave
end try

public static void Main(Args _args)
{
   try
   {
      // Code that could throw an exception.
   }
   catch (Exception::Error) // Or any other exception type.
   {
      // Process the error.
   }
   catch
   {
      // Process any other exception type not handled previously.
   }

   // Code here will execute as long as any exception is caught.
}

1. ^ Bjarne Stroustrup’s FAQ
2. ^ «Handling exceptions». Archived from the original on 2014-01-02. Retrieved 2014-01-01.
3. ^ «Exception handling tags». Archived from the original on 2014-01-02. Retrieved 2014-01-01.
4. ^ https://issues.jboss.org/browse/RAILO-2176 # JBoss Community issue tracker ticket for adding retry
5. ^ Borland, Delphi Version 7.0, Online help
6. ^ «Pharo by Example». Archived from the original on 2009-10-21. Retrieved 2010-03-20.
7. ^ ^{a b} Try-Catch for VB
8. ^ http://wiki.visual-prolog.com/index.php?title=Language_Reference/Terms#Try-catch-finally

if ! command; then
    echo "command returned an error"
fi

<command_1> || <command_2>

error_exit()
{
    echo "Error: $1"
    exit 1
}

bad-command || error_exit "Some error"

status=$?

case "$status" in
"1") echo "General error";;
"2") echo "Misuse of shell builtins";;
"126") echo "Command invoked cannot execute";;
"128") echo "Invalid argument";;
esac

set -e
# некоторый критический блок кода, где ошибка недопустима
set +e

set -e
true | false | true
echo "Это будет напечатано" # "false" внутри конвейера не обнаружено

set -o pipefail -e
true | false | true # "false" внутри конвейера определен правильно
echo "Это не будет напечатано"

set -o pipefail -e
# некоторый критический блок кода, в котором не допускается ошибка или ошибка конвейера
set +o pipefail +e