Mail Archives: cygwin/2001/04/24/13:39:02
>From: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
>To: "Nicholas Peters" <nickapeters AT hotmail DOT com>, <cygwin AT cygwin DOT com>
>Subject: RE: Linking Cygwin & MSVC objects / libraries using MSVC linker
>Date: Tue, 24 Apr 2001 10:55:15 +1000
>
> > -----Original Message-----
> > From: Nicholas Peters [mailto:nickapeters AT hotmail DOT com]
> > Sent: Tuesday, April 24, 2001 10:59 AM
> > To: cygwin AT cygwin DOT com
> > Subject: Linking Cygwin & MSVC objects / libraries using MSVC linker
> >
> >
> > Is it possible to link Cygwin compiled objects and Microsoft
> > Visual C (not
> > C++) objects using the libcygwin.a and it's associated libraries and
> > Microsofts various libraries (MSVCRT, etc). I would very
> > much like to use
>
>lybcygwin.a is mainly an import lib for cygwin1.dll aka libm aka libc
>aka lpthread aka I'm not shure howmanyotherlibraries.
>
> > the MSVC linker for this (not ld) but am open to all ideas.
> > When I tried
> > to just flat out link (with MSVC linker) I got some errors
> > from libcygwin.a
> > stating it had undefined external references to data_start, data_end,
> > bss_start, bss_end. After reading through some of the mail
> > archives for
> > this list I decided to throw in some null char declarations for those
> > references since I'm not using the fork functionality of
> > libcygwin. I get
> > two warnings in the link, and the resulting exe crashes.
> >
> > The warnings are:
> > libcygwin.a : warning multiple ".idata" sections found with different
> > attributes.
> >
> > libcygwin.a : warning __fmode already defined in MSVCRT.LIB second
> > definition ignored.
> >
> > When I list libcygwin.a BEFORE MSVCRT in my link command
> > line, the second
> > warning changes to:
> >
> > MSVCRT.LIB : warning _atexit already defined in libcygwin.a second
> > definition ignored.
> >
> > Either way the the produced executable crashes with "The
> > instruction at
> > <address> referenced memory at <address>. The memory could
> > not be "read". "
>
>AFAIK you cannot mix MSVCRT.LIB and libcygwin.a. They implement the same
>functions. What do you need from cygwin?
I need mostly socket stuff, the link (with MSVC) without libcygwin.a
produces:
: error LNK2001: unresolved external symbol _gethostname
: error LNK2001: unresolved external symbol _sleep
: error LNK2001: unresolved external symbol __imp___ctype_
: error LNK2001: unresolved external symbol _accept
: error LNK2001: unresolved external symbol _select
: error LNK2001: unresolved external symbol _listen
: error LNK2001: unresolved external symbol _bind
: error LNK2001: unresolved external symbol _setsockopt
: error LNK2001: unresolved external symbol _socket
: error LNK2001: unresolved external symbol _htons
: error LNK2001: unresolved external symbol _getservbyname
: error LNK2001: unresolved external symbol __impure_ptr
: error LNK2001: unresolved external symbol __impure_ptr
From previous experience I believe I can safely ignore the impure_ptr
errors (by forcing the link with /FORCE), and if you know what libraries to
strip out of libcygwin to get the above symbols taken care of that would be
great. Thanks for responding.
Nick
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