Mailing-List: contact cygwin-help AT sourceware DOT cygnus DOT com; run by ezmlm
Sender: cygwin-owner AT sources DOT redhat DOT com
Message-ID: <17B78BDF120BD411B70100500422FC6309E21F@IIS000>
From: Bernard Dautrevaux <Dautrevaux AT microprocess DOT com>
To: "'robert DOT jan DOT schutten AT philips DOT com'" <robert DOT jan DOT schutten AT philips DOT com>,
        cygwin AT sources DOT redhat DOT com
Subject: RE: How to compile a .LIB with cygwin for use in MS Visual C
Date: Wed, 28 Feb 2001 17:46:44 +0100
MIME-Version: 1.0
Content-Type: text/plain;
	charset="iso-8859-1"

> -----Original Message-----
> From: robert DOT jan DOT schutten AT philips DOT com
> [mailto:robert DOT jan DOT schutten AT philips DOT com]
> Sent: Wednesday, February 28, 2001 4:45 PM
> To: cygwin AT sources DOT redhat DOT com
> Subject: How to compile a .LIB with cygwin for use in MS Visual C
> 
> 
> Hi all,
> 
> I am trying to compile library using cygwin. This library compiles
> perfectly with gcc on various unix platforms and with the 
> cygwin version
> on gcc on a MS-windows machine. Also usage of this library is
> working perfectly on all these platforms.
> 
> Now the problem:
> 
> I would like to use the compiles library as a .LIB under MS Visual C.
> 
> So why don't I just distribute source code of my library so that it
> can be compiled with Visual C.
> Reason: I rely on automatic source code generation, which works
> with a combination of makefiles and standard unix tools. This is
> difficult to port to Visual C.
> 
> What did I try:
> 
> I tried including my library (it's called  libcpfspd.a) at 
> the linking stage
> of Visual C by just adding this to the line "Object/library modules"
> 
> I get the following linking error:
> 
> --------------------Configuration: cpfspd_test2 - Win32 
> Release--------------------
> Linking...
> libcpfspd.a(cpfspd_hdr.o) : error LNK2001: unresolved 
> external symbol __impure_ptr
> libcpfspd.a(cpfspd_low.o) : error LNK2001: unresolved 
> external symbol __impure_ptr
> libcpfspd.a(cpfspd_low.o) : error LNK2001: unresolved 
> external symbol __alloca
> libcpfspd.a(cpfspd_low.o) : error LNK2001: unresolved 
> external symbol ___errno
> Release/cpfspd_test2.exe : fatal error LNK1120: 3 unresolved externals
> Error executing link.exe.
> 
> cpfspd_test2.exe - 5 error(s), 0 warning(s)
> 
> Next try: compile the library with -mno-cygwin:
> Following result:
> 
> --------------------Configuration: cpfspd_test2 - Win32 
> Release--------------------
> Linking...
> libcpfspd-mno-cygwin.a(
> ) : error LNK2001: unresolved external symbol ___imp__iob
> libcpfspd-mno-cygwin.a(
> ) : error LNK2001: unresolved external symbol ___imp__iob
> libcpfspd-mno-cygwin.a(
> ) : error LNK2001: unresolved external symbol __alloca
> Release/cpfspd_test2.exe : fatal error LNK1120: 2 unresolved externals
> Error executing link.exe.
> 
> cpfspd_test2.exe - 4 error(s), 0 warning(s)
> 
> 
> So, is it possible to compile with cygwin and use the result 
> with Visual C, 
> or am I asking for the impossible?
> 


I'm not sure of the exact procedure to follow, but at least you must use
-mno-cygwin when compiling this kind of code (and you must check the the
mingw32 support is properly installed, depending on your cygwin version).
This was already discussed a number of times on this list so e search of the
archive should provide the necessary links. 

In fact to interoperate with Visual-C code you MUST compile in MinGW32 mode,
not cygwin. Moreover you can ONLY share C code (that's why I say Visual-C
and not Visual-C++); gcc-generated C++ code cannot be called from
Visual-C++-compiled C++ code, nor the other way round. They cannot and would
most certainly NEVER work together.

HTH

	Bernard

--------------------------------------------
Bernard Dautrevaux
Microprocess Ingenierie
97 bis, rue de Colombes
92400 COURBEVOIE
FRANCE
Tel:	+33 (0) 1 47 68 80 80
Fax:	+33 (0) 1 47 88 97 85
e-mail:	dautrevaux AT microprocess DOT com
		b DOT dautrevaux AT usa DOT net
-------------------------------------------- 

--
Want to unsubscribe from this list?
Check out: http://cygwin.com/ml/#unsubscribe-simple