email and Windows sockets API error return codes

Winsock Error Codes - This Page 1/3

User Fixable Errors - There are two basic types of errors: those an application user can remedy, and those he cannot and a user should never see an error that is not user-fixable and list of user-fixable errors... Page 2/3

List of user-fixable errors - Continue - Page 3/3

RFC defined ESMTP Status Error Codes

ESMTP Status Error Codes Command Group

Definition of extension to the SMTP service RFC-821

Mail Object Error Message

Return error codes by Windows Sockets API

Winsock Error Codes The following is a list of error codes returned by the WSAGetLastErrorcall along with their descriptions

There are two kinds of errors in Windows Sockets: task-based (or thread-based) and socket-based. An application can retrieve the task-based error by calling WSAGetLastError() www.sockets.com/winsock.htm#GetLastError
immediately after a WinSock function fails:

reported in a WSAAsyncSelect() www.sockets.com/winsock.htm#AsyncSelect asynchronous FD_ event notification message (which you can extract with the platform independent "message cracker" macro WSAGETSELECTERROR(lParam)).
retrieved by a call to getsockopt() SO_ERROR (which also resets the error value to zero).
www.sockets.com/winsock.htm#GetSockOpt

WSAStartup() www.sockets.com/winsock.htm#Startup is the only function that returns an actual error value, rather than simply indicating an error condition (function failure).

This makes sense, since you can't call WSAGetLastError() to retrieve the error value until WSAStartup() succeeds since it will fail with WSANOTINITIALISED www.sockets.com/err_lst1.htm#SANOTINITIALISED

Windows Sockets does not support the Berkeley Sockets error variables errno or h_errno because these per-process global variables don't allow for per-thread error information.

The WINSOCK.H header file provides a macro for h_errno for Berkeley source code compatibility--simply calls WSAGetLastError() The equivalent macro for errno wasn't included since some applications use errno for non-socket (e.g. file handle) errors.

Most of the error values and their manifest constants (macros) are derived from Berkeley Sockets. The WinSock error values are the BSD error values with a "WinSock API base" error WSABASEERR www.sockets.com/err_lst1.htm#WSABASEERR value added to each of them.

The macro for each WinSock API error is the equivalent BSD error's macro, with the three letters WSA prepended to it. So, for instance, the BSD manifest constant for the "would block" error was defined in the Berkeley Sockets ERRNO.H header file as:

#define  EWOULDBLOCK  35

and WINSOCK.H redefines it as:

#define  WSAEWOULDBLOCK  (WSABASEERR+35)
www.sockets.com/err_lst1.htm#WAEWOULDBLOCK

A few (lower value) WinSock error macro definitions refer to Microsoft C constants. In some cases, these redefine file access errors since Windows NT can treat a socket like a file handle.

A few other (higher value) macros are entirely new to Windows Sockets. They refer to error conditions unique to Windows Sockets, such as invalid WinSock version requests, uninitialized WinSock DLL access, or failed hostname resolution attempts.

All of the Windows Sockets error values have macros defined for them in the WINSOCK.H header file. They all have a "WSA" prefix and their values are all biased by the WinSock API base error WSABASEERR (10000) value.
See list of user-fixable errors... Next page 2/3

Click button to

Manage bounce
returned email
freeware

Free2Try
Easy to use
PC anti spam

Sun Tzu
Art of War
Free eBook

The value for WSABASEERR is fairly arbitrary. It's high simply because error values in the Windows API are high values by convention. There is a benefit, though: the unique bias creates identifiable WinSock error values.

What Errors to Expect?
Don't assume the only errors you'll encounter are the ones listed with each function in the WinSock specification. Section 3.3.4 "Error Handling" in the v1.1 Windows Sockets specification warns against this:

Note that this specification defines a recommended set of error codes, and lists the possible errors which may be returned as a result of each function. It may be the case in some implementations that other Windows Sockets error codes will be returned in addition to those listed, and applications should be prepared to handle errors other than those enumerated under each API description.

The specification is a common denominator among WinSock implementations. The errors it lists don't provide "fine resolution" in all cases, which means it doesn't account for some conditions that some network systems can detect.

Finer resolution in error reporting is a double edged sword: with more accurate error values it's easier to diagnose problems when they occur, but it's also more difficult to write an application that can handle all contingencies. The better prepared your application is for any error, the more gracefully you'll handle it, and the easier you'll make your job and the job of your support staff.

Dolly
Kee
Director

ImagePower.com.my
eMail CRM maximized
the life-time value of
my customers.
I recommend it.

For home office PC
Freeware

Next page 2/3
User Fixable Errors - There are two basic types of errors: those an application user can remedy, and those he cannot and a user should never see an error that is not user-fixable and list of user-fixable errors... Next page 2/3

List of user-fixable errors - Continue - Page 3/3

<<back to>> eMail Bolts&Nuts

Click button & YOU can ...