Fortran and Mixed Language Codes on the FASRC cluster

In order to cross-compiled mixed Fortran and C code on the cluster using GNU compilers, let us look at the following simple codes:

$ cat cfortran.f
C Check for NAN
C
PROGRAM checknum
IMPLICIT NONE
REAL fnum
INTEGER isnan
INTEGER isinf
INTEGER isit
fnum=log(0.)
isit=isinf(fnum)
WRITE (*,*) isit
STOP
END
[hptc@iliadaccess02 cfortran]$ cat checknan.c
#include
#include int isnan_(float *fnum)
{
if (isnan( *fnum) != 0)
{
return 1;
}
return 0;
}
int isinf_(float \*fnum)
{
if (isinf(\*fnum) != 0)
{
return 1;
}
return 0;
}

Note: The underscores in the C function names are necessary.
Use the following Makefile:

$ cat Makefile
CC=gcc
F77=g77
CFLAGS=-g
FFLAGS=-g
LIB=-lm
RM=/bin/rm -f
EXE = cfortran
OBJ = cfortran.o checknan.o
$(EXE): $(OBJ) Makefile
$(F77) $(FFLAGS) -o $(EXE) $(OBJ) $(LIB)
.f.o:
$(F77) $(FFLAGS) -o $*.o -c $*.f
.c.o:
$(CC) $(CFLAGS) -o $*.o -c $*.c
clean:
$(RM) $(EXE) $(OBJ) *~

This gives:

[hptc@iliadaccess02 cfortran]$ make
g77 -g -o cfortran.o -c cfortran.f
gcc -g -o checknan.o -c checknan.c
g77 -g -o cfortran cfortran.o checknan.o -lm
[hptc@iliadaccess02 cfortran]$ ./cfortran
1

As log(0) is infinite, the program answers 1.

Last UpdatedApril 29, 2024

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Fortran and Mixed Language Codes on the FASRC cluster