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                  PTHREADS-WIN32 Frequently Asked Questions


Q 1	How do I get pthreads-win32 to link under Cygwin32 or Mingw32?


Q 1	How do I get pthreads-win32 to link under Cygwin32 or Mingw32?

A 1
The following email from Anders Norlander explains how to solve this
problem. I think the proviso is that the DLL and your application should
both be built with the same development environment (cygwin, mingw,
or MSVC etc).

Date: Mon, 07 Dec 1998 15:11:37 +0100
From: Anders Norlander <anorland@hem2.passagen.se>
To: Ross Johnson <rpj@ise.canberra.edu.au>
Cc: pthreads-win32 <pthreads-win32@air.net.au>
Subject: Re: pthreads-win32: TryEnterCriticalSection patch (fwd)

Ross Johnson wrote:
> Anders,
> You said you're using GCC. Is that from cygwin32 or mingw32? What is your
> environment (so I can perhaps help other people out)? We have problems
> with cygwin32 et al that have been built on Win95. They're missing
> _{begin,end}threadex.


I use mingw32 when compiling pthreads-win32, but unlike most people I
use MSVCRT as the C library instead of CRTDLL. For those that don't
feel like configuring and building the necessary components themselves,
Mumit Khan has released an add on for mingw32 to make it use MSVCRT40.
It is available at his ftp site, follow the minw32 links at

For cygwin it is a completely different matter. I suppose
pthreads-win32 uses _beginthreadex and _endthreadex because the Win32
docs say that programs calling functions in the C library should not
use CreateThread and ExitThread. However, this applies only to
Microsoft's (and possibly others) multithreaded C libraries that need
to keep track of per thread data, it does not apply to cygwin.
This code solves the problem:

/* Check for old and new versions of cygwin */
#if defined(__CYGWIN32__) || defined(__CYGWIN__)
/* Macro uses args so we can cast start_proc to LPTHREAD_START_ROUTINE
   in order to avoid warnings because of return type */
#define _beginthreadex(security, stack_size, start_proc, arg, flags,
pid) \
CreateThread(security, stack_size, (LPTHREAD_START_ROUTINE) start_proc,
             arg, flags, pid)
#define _endthreadex ExitThread

I would be extremely careful using threads with cygwin, since it is
not (yet) threadsafe.