Re: fortran and C mixed-language program - cygwin the way to go?

[Larry Hall <cygwin-lh at cygwin dot com>]

At 04:00 AM 5/4/2004, you wrote:
>Hi,
>
>I don't know if this is the right list to post this question to, but please bear
>with me.
>
>I'm using cygwin on windows XP.  I have a large fortran 95 program that I
>compile with Compaq Visual Fortran 6.6.  There is no way g77 will handle the
>fortran 9x features I'm using, and g95 is still larval.  So let's take the
>fortran compiler as fixed.
>
>I want to use FFTW, the open-source fft library from mit (www.fftw.org), in the
>code.  FFTW is written in C.  Its make process can setup wrapper functions for
>calling FFTW routines from fortran.  I think I figured out the right way to
>configure the wrappers for my fortran compiler.
>
>The problem is linking it all togheter.  I'm using DF (the compaq visual fortran
>command-line compiler) to control the compilation of the fortran, and the
>linking of the final exe.  I setup a small test suite of a fortran caller and C
>function, and DF compiles them correctly.  Not quite there with fftw.
>
>I can compile the fortran with DF, and the C with gcc under cygwin.  I then try
>linking them together.  If I don't include libfftw.a in the linking, DF can't
>find the fftw routines.  If I include libfftw.a, then it can.
>
>BUT, df can then not find what look like low-level C routines, like ___getreent
>and ___gettimeofday.  From poking around on the web I found out that ___getreent
>is in libpthread.a on cygwin.  I can't get the others to work.
>
>
>I have no idea if my approach (compile fortran and link w/ df, compile the fftw
>C library w/ gcc for cygwin) is a good idea, or possible at all.  Any advice on
>a good approach would be very greatly appreciated.  I'm not an expert on
>compilers, all I want is something that'll let me use a C library in fortran. 
>And hopefully not make me buy a C compiler!


Try using 'gcc -mno-cygwin'.  Since you're firmly in the Win32 environment
with your Win32 Fortran compiler, you're better off not mixing the 
Cygwin POSIX DLL into the equation.  This may cause you to do some porting
perhaps, depending on the features in FFTW.  Still, their web site claims
that FFTW will build with VC++ 6 or Intel's compiler so there must not be
much reliance on POSIX APIs. 


--
Larry Hall                              http://www.rfk.com
RFK Partners, Inc.                      (508) 893-9779 - RFK Office
838 Washington Street                   (508) 893-9889 - FAX
Holliston, MA 01746                     


--
Unsubscribe info:      http://cygwin.com/ml/#unsubscribe-simple
Problem reports:       http://cygwin.com/problems.html
Documentation:         http://cygwin.com/docs.html
FAQ:                   http://cygwin.com/faq/