Re: Fix Windows socket error checking for MinGW

On Fri, Aug 16, 2013 at 06:56:45PM -0500, Michael Cronenworth wrote:
> I started a thread on the general list so read that for more info.
>
> http://www.postgresql.org/message-id/520A6E55.40901@cchtml.com
>
> I'm also going to submit the patch to CommitFest.

> +#ifndef WIN32
> if (SOCK_ERRNO == EWOULDBLOCK)
> +#else
> + if (SOCK_ERRNO == WSAEWOULDBLOCK)
> +#endif

Thanks for looking into this. I suspect this patch is achieving the right
runtime behavior, but some cleanup is in order. src/include/port/win32.h
makes some effort to preempt the need for a patch like this, but the relevant
code isn't used for MinGW:

/*
* For Microsoft Visual Studio 2010 and above we intentionally redefine
* the regular Berkeley error constants and set them to the WSA constants.
* Note that this will break if those constants are used for anything else
* than Windows Sockets errors.
*/
#if _MSC_VER >= 1600
#pragma warning(disable:4005)
#define EMSGSIZE WSAEMSGSIZE
#define EAFNOSUPPORT WSAEAFNOSUPPORT
#define EWOULDBLOCK WSAEWOULDBLOCK
#define EPROTONOSUPPORT WSAEPROTONOSUPPORT
#define ECONNRESET WSAECONNRESET
#define EINPROGRESS WSAEINPROGRESS
#define ENOBUFS WSAENOBUFS
#define ECONNREFUSED WSAECONNREFUSED
#define EOPNOTSUPP WSAEOPNOTSUPP
#pragma warning(default:4005)
#endif

I suspect we should do one of the following:

1. Redefine those constants for more (all?) compilers.
2. Remove that block and put #ifdef around all usage of such constants in
frontend code, as you have done.
3. Remove that block and make src/backend/port/win32/socket.c frontend-usable,
so frontend code can treat errno like backend code treats errno.

What do you recommend?

Thanks,
nm

--
Noah Misch
EnterpriseDB http://www.enterprisedb.com