Hi guys....I've spent the whole night trying to figure out about this
question. Please help me if you have any clue. Thanks a lot.
The code is very easy. I'm trying to call a fortran function from C.
The code is as follow:
=========C code=========
#include "stdio.h"
extern float r_ (int * d, float *b);
main ()
{
float a = 1.5, b = 1.05, c = 1;
int d = 2;
c = r_ (&d, &b);
printf ("%f\n", c);
}
==========Fortran Code===========
real function r(m,t)
integer m
real t
print *, m, t
r = 0.1*t+46
print *, r
return
end
================================
It doesn't matter what the fortran code does...but when I compile it
with g77, the result can't be passed back to the C code, but with
gfortran, it can. Here are the outputs:
***fortran code compiled by gfortran****
[du@[EMAIL PROTECTED]
qr]$ gfortran -funroll-all-loops -O3 -c ceiling.f -o
ceiling.o;gcc -funroll-all-loops -O3 -c testint.c -o testint.o;g77 -o
testint.x testint.o ceiling.o -L/pkgs/intel/mkl/9.0/lib/em64t -L/home/
du/lib/hpl/lib/LINUX_XEON_QUAD -L/usr/lib/gcc/x86_64-redhat-linux/
3.4.6/ -L/usr/lib/gcc/x86_64-redhat-linux/4.1.1 -L. -lgfortran
[du@[EMAIL PROTECTED]
qr]$ ./testint.x
2 1.050000
46.10500 <----------- result in Fortran function
46.105000 <--------- result received by C code
***fortran code compiled by g77****
[du@[EMAIL PROTECTED]
qr]$ g77 -funroll-all-loops -O3 -c ceiling.f -o
ceiling.o;gcc -funroll-all-loops -O3 -c testint.c -o testint.o;g77 -o
testint.x testint.o ceiling.o -L/pkgs/intel/mkl/9.0/lib/em64t -L/home/
du/lib/hpl/lib/LINUX_XEON_QUAD -L/usr/lib/gcc/x86_64-redhat-linux/
3.4.6/ -L/usr/lib/gcc/x86_64-redhat-linux/4.1.1 -L. -lgfortran
[du@[EMAIL PROTECTED]
qr]$ ./testint.x
2 1.04999995
46.1049995
-0.000000 <----------- but here I get 0, with the only difference in
the way the fortran code is compiled.
Here are the versions:
[du@[EMAIL PROTECTED]
qr]$ g77 -v
Reading specs from /usr/lib/gcc/x86_64-redhat-linux/3.4.6/specs
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --
infodir=/usr/share/info --enable-shared --enable-threads=posix --
disable-checking --with-system-zlib --enable-__cxa_atexit --disable-
libunwind-exceptions --enable-languages=c,c++,f77 --disable-libgcj --
host=x86_64-redhat-linux
Thread model: posix
gcc version 3.4.6 20060404 (Red Hat 3.4.6-4)
[du@[EMAIL PROTECTED]
qr]$ gfortran -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --
infodir=/usr/share/info --enable-shared --enable-threads=posix --
enable-checking=release --with-system-zlib --enable-__cxa_atexit --
disable-libunwind-exceptions --enable-libgcj-multifile --enable-
languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --
disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.4.2-
gcj-1.4.2.0/jre --with-cpu=generic --host=x86_64-redhat-linux
Thread model: posix
gcc version 4.1.2 20070626 (Red Hat 4.1.2-13)
[du@[EMAIL PROTECTED]
qr]$ gcc -v
Using built-in specs.
Target: x86_64-redhat-linux
Configured with: ../configure --prefix=/usr --mandir=/usr/share/man --
infodir=/usr/share/info --enable-shared --enable-threads=posix --
enable-checking=release --with-system-zlib --enable-__cxa_atexit --
disable-libunwind-exceptions --enable-libgcj-multifile --enable-
languages=c,c++,objc,obj-c++,java,fortran,ada --enable-java-awt=gtk --
disable-dssi --enable-plugin --with-java-home=/usr/lib/jvm/java-1.4.2-
gcj-1.4.2.0/jre --with-cpu=generic --host=x86_64-redhat-linux
Thread model: posix
gcc version 4.1.2 20070626 (Red Hat 4.1.2-13)
THANKS AGAIN FOR THE HELP!
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