Visual Studio linking

Daniel Starin
Fri Dec 17 21:35:00 GMT 2004

So, I realized I had the compile option "Use Managed Extensions" on in VS
.NET and that was causing the problem.  Now that I can include the libs in
my project, are there any header files that I can include from Visual Studio
to use them?...

When I include <pthread.h> from the cygwin/usr/include directory, for
example, I get errors like this...

C:\cygwin\usr\include\sys\_types.h(15) : error C2144: syntax error :
'__int64' should be preceded by ';'
C:\cygwin\usr\include\sys\_types.h(15) : error C2501: '__extension__' :
missing storage-class or type specifiers



-----Original Message-----
From: [] On Behalf Of
Larry Hall
Sent: Sunday, December 12, 2004 5:51 PM
To: Daniel Starin;
Subject: Re: Visual Studio linking

At 05:39 PM 12/12/2004, you wrote:
>    I am also trying to use functions implemented in cygwin1.dll with
>Visual Studio as discussed below.  After started a blank console
>and following steps below, I get to linking which gives me the following
>LIBCMTD.lib(crt0.obj) : error LNK2005: _mainCRTStartup already defined in
>Any suggestions?

Sure.  Duck and run!  

You're clearly getting both the Cygwin and MS C run times linked in, which
suggests you're using functionality from both.  This can be dangerous in
the extreme if you don't know what you're doing.  In your particular case, 
you end up trying to link against CRT initialization routines from both
libraries, which is clearly a recipe for disaster if it's not handled 
correctly.  Doing this type of thing as the series of steps provided is no
better than a work-around.  It may work.  It may not.  If Alastair is
to help you out with your case, that's great.  But you should be warned 
that his approach isn't supported.  Use it at your own risk.  We're still
looking for someone who's interested enough in this subject to re-enable 
automatic support for this in the Cygwin DLL itself.  But it's been years
since it worked and the level of interest by anyone on this list has never 
produced results unfortunately...

Larry Hall                    
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
838 Washington Street                   (508) 893-9889 - FAX
Holliston, MA 01746                     

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