Remembering numeric error codes is hard.  Unless the error handling code is well documented, code reviews take longer and maintenance is more difficult as you may need to consult reference manuals, native code header files or online help frequently.

Socket errors are particularly hard for me to remember.  To help myself out, I have collected Windows Sockets error codes into a couple of enums.

The first enum, SocketErrorCodes uses friendly descriptions based on the following Microsoft Support article .  For detailed descriptions of the error codes, please refer to this article or a Windows Sockets reference.

public enum SocketErrorCodes
{
    InterruptedFunctionCall         = 10004,
    PermissionDenied                = 10013,
    BadAddress                      = 10014,
    InvalidArgument                 = 10022,
    TooManyOpenFiles                = 10024,
    ResourceTemporarilyUnavailable  = 10035,
    OperationNowInProgress          = 10036,
    OperationAlreadyInProgress      = 10037,
    SocketOperationOnNonSocket      = 10038,
    DestinationAddressRequired      = 10039,
    MessgeTooLong                   = 10040,
    WrongProtocolType               = 10041,
    BadProtocolOption               = 10042,
    ProtocolNotSupported            = 10043,
    SocketTypeNotSupported          = 10044,
    OperationNotSupported           = 10045,
    ProtocolFamilyNotSupported      = 10046,
    AddressFamilyNotSupported       = 10047,
    AddressInUse                    = 10048,
    AddressNotAvailable             = 10049,
    NetworkIsDown                   = 10050,
    NetworkIsUnreachable            = 10051,
    NetworkReset                    = 10052,
    ConnectionAborted               = 10053,
    ConnectionResetByPeer           = 10054,
    NoBufferSpaceAvailable          = 10055,
    AlreadyConnected                = 10056,
    NotConnected                    = 10057,
    CannotSendAfterShutdown         = 10058,
    ConnectionTimedOut              = 10060,
    ConnectionRefused               = 10061,
    HostIsDown                      = 10064,
    HostUnreachable                 = 10065,
    TooManyProcesses                = 10067,
    NetworkSubsystemIsUnavailable   = 10091,
    UnsupportedVersion              = 10092,
    NotInitialized                  = 10093,
    ShutdownInProgress              = 10101,
    ClassTypeNotFound               = 10109,
    HostNotFound                    = 11001,
    HostNotFoundTryAgain            = 11002,
    NonRecoverableError             = 11003,
    NoDataOfRequestedType           = 11004
}

The second, WinSockErrorCodes, uses the symbolic names you see in native WinSock application code.

public enum WinSockErrorCodes
{
    WSAEINTR           = 10004,
    WSAEACCES          = 10013,
    WSAEFAULT          = 10014,
    WSAEINVAL          = 10022,
    WSAEMFILE          = 10024,
    WSAEWOULDBLOCK     = 10035,
    WSAEINPROGRESS     = 10036,
    WSAEALREADY        = 10037,
    WSAENOTSOCK        = 10038,
    WSAEDESTADDRREQ    = 10039,
    WSAEMSGSIZE        = 10040,
    WSAEPROTOTYPE      = 10041,
    WSAENOPROTOOPT     = 10042,
    WSAEPROTONOSUPPORT = 10043,
    WSAESOCKTNOSUPPORT = 10044,
    WSAEOPNOTSUPP      = 10045,
    WSAEPFNOSUPPORT    = 10046,
    WSAEAFNOSUPPORT    = 10047,
    WSAEADDRINUSE      = 10048,
    WSAEADDRNOTAVAIL   = 10049,
    WSAENETDOWN        = 10050,
    WSAENETUNREACH     = 10051,
    WSAENETRESET       = 10052,
    WSAECONNABORTED    = 10053,
    WSAECONNRESET      = 10054,
    WSAENOBUFS         = 10055,
    WSAEISCONN         = 10056,
    WSAENOTCONN        = 10057,
    WSAESHUTDOWN       = 10058,
    WSAETIMEDOUT       = 10060,
    WSAECONNREFUSED    = 10061,
    WSAEHOSTDOWN       = 10064,
    WSAEHOSTUNREACH    = 10065,
    WSAEPROCLIM        = 10067,
    WSASYSNOTREADY     = 10091,
    WSAVERNOTSUPPORTED = 10092,
    WSANOTINITIALIZED  = 10093,
    WSAEDISCON         = 10101,
    WSATYPE_NOT_FOUND  = 10109,
    WSAHOST_NOT_FOUND  = 11001,
    WSATRY_AGAIN       = 11002,
    WSANO_RECOVERY     = 11003,
    WSANO_DATA         = 11004
}

I find the descriptive enum (SocketErrorCodes) most useful when I am writing new code.  The WinSockErrorCodes enum is handy when porting native code to .NET.  With either enum, I can simply cast the Int32 found in SocketException.ErrorCode to the appropriate enum to make my code easier to read and maintain.  For example:

try
{
    // code that causes a SocketException
}
catch(SocketException se)
{
    SocketErrorCodes errorCode = (SocketErrorCodes)se.ErrorCode;
   
    switch(errorCode)
    {
        case SocketErrorCodes.PermissionDenied:
            // error handling
            break;

        case SocketErrorCodes.AddressInUse:
            // error handling
            break;

        // etc..
    }
}

As mentioned earlier, the data used to create the above enums can be found here .  Of course, any mistakes you may find here are entirely mine.  When in doubt, please consult the support article or a Windows Sockets reference.

Until next time,
-- DK

[Edit: fix typeo]

Disclaimer(s):
This posting is provided "AS IS" with no warranties, and confers no rights.