RE: Linking in WSAGetLastError

["Michael Olson" <olson@cs.odu.edu>]

To link with a DLL (Like user32.dll) you need an import library which is
what -luser32
is linking your program to. Doc's on how to build dll's and import libraries
are here
http://sources.redhat.com/cygwin/cygwin-ug-net/dll.html

Is that what you were looking for?

-- Mike

----------------
Michael Olson
olson@cs.odu.edu
----------------

-----Original Message-----
From: cygwin-owner@sources.redhat.com
[ mailto:cygwin-owner@sources.redhat.com]On Behalf Of Ed
Bradford/Raleigh/IBM
Sent: Wednesday, September 27, 2000 9:43 AM
To: DJ Delorie
Cc: cygwin@sourceware.cygnus.com
Subject: Re: Linking in WSAGetLastError


I'm missing something here. If the CYGWIN libraries don't export functions
(aren't current with MS API's) then
you simply can't use the function. At least that's what I thought. After a
few simple experiments, I find that I might be wrong. Is there something
written somewhere that describes the relationship between
     gcc msg.c
and the Microsoft libraries? For instance, using gcc -v I see no references
to the mssdk libraries. Is that
because there isn't any? Here is my simple "msg.c" program:

     #include <windows.h>

     int main(int ac, char *av[])
     {
          MessageBox(NULL, "Messsage", "Title", MB_OK);
          return 0;
     }

It compiles with either
     cl msg.c user32.lib -o msg-cl.exe
or
     gcc msg.c -o msg-gcc
Both compile, link and execute properly. More precisely,

   gcc -c msg.c
   ld -Bdynamic /lib/crt0.o msg.o -L/usr/lib/gcc-lib/i686-pc-cygwin/2.95.2
   -luser32 -lcygwin -lkernel32

produces a correctly working executable. Here, all the "-l" things refer to
/lib/libXXX.a modules. Substituting
//e/mssdk/lib/user32.lib for the "-luser" in the ld line, results in an
undefined reference to MessageBoxA
which is what I would expect.

As you can see, I am a bit confused. Any pointers to writeups on how all
the gcc libraries and
Windows libraries fit together would be greately appreciated. Also, I
wouldn't mind writing some of this
up once I understand it.

Thank you
Ed Bradford



Your Windows 2000 Arborist
T/L 589-4410; Outside: 1-919-993-4410
egb@us.ibm.com


DJ Delorie <dj@delorie.com>@sources.redhat.com on 09/26/2000 09:33:12 PM

Sent by:  cygwin-owner@sources.redhat.com


To:   olson@cs.odu.edu
cc:   cygwin@sourceware.cygnus.com
Subject:  Re: Linking in WSAGetLastError




> conf.o(.text+0x2c74):conf.c: undefined reference to `WSAGetLastError'

They don't export WGAGetLastError.  They export WSAGetLastError@0.
This means that you aren't including the proper headers (winsock.h),
and it's defaulting to cdecl instead of stdcall (WINAPI) calling
conventions.

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