forums.silverfrost.com

[Norm.Campbell]

Your reply stated that:

"To provide a link between Fortran and C you will need to use C_EXTERNAL statements in the Fortran and export your C routines in a specific way. Its not so tricky and the manual has info on this at:

Win32 Platform->Mixed Language Programming->Calling C/C++ from FTN95

Basically you need to add extern "C" to your C routine definitions and create corresponding C_EXTERNAL definitions in your Fortran. The C routines will need exporting from the DLL (depends on the C compiler you are using exactly how this is done). You can then link directly with the DLL using SLINK (no need for lib files). "

>> I'm using the Salford C compiler, scc, at this stage

Would you please be able to take a couple of minutes to make the necessary modifications to the following example code, as this will save me (and probably you) an awful lot of time.


program test_wrapper


dimension xxx(10), yyy(10)


npt = 10

do ip = 1, npt

xxx(ip) = ip

yyy(ip) = 1.

end do


xv1 = 20.
yv1 = 30.


itt = 6


call wrap_c_to_Fortran ( itt, npt, xxx, yyy, xpr,
1 xv1, yv1, pv1 )



stop
end



c I would like to be able to replace this subroutine
c by C code (see my first try below)

c and make whatever changes are necessary to the remaining Fortran
c and modified c code to have the example compile and run


subroutine wrap_c_to_Fortran ( itt, npt, xxx, yyy, xpr,
1 xv1, yv1, pv1 )

dimension xxx(*), yyy(*)


c write data

write (itt,'(/ '' XXX '')' )

write (itt,'( 10g12.4 )') (xxx(ip),ip=1,npt)

do ip = 1, npt

write (itt,'(/ '' XXX(i) '', g12.4 )') xxx(ip)

end do


write (itt,'(/ '' YYY '')' )

write (itt,'( 10g12.4 )') (yyy(ip),ip=1,npt)

do ip = 1, npt

write (itt,'(/ '' YYY(i) '', g12.4 )') yyy(ip)

end do


write (itt,'(/ '' XV1 '', g12.4 )') xv1

write (itt,'(/ '' YV1 '', g12.4 )') yv1



call calc_prod ( npt, xxx, yyy, xpr, xv1, yv1, pv1 )


write (itt,'(/ '' XXX * YYY = '', g12.4 )') xpr

write (itt,'(/ '' XV1 * YV1 = '', g12.4 )') pv1


return
end





subroutine calc_prod ( npt, xxx, yyy, xpr, xv1, yv1, pv1 )


dimension xxx(*), yyy(*)


xpr = 0.

do ip = 1, npt

xpr = xpr + xxx(ip) * yyy(ip)

end do

pv1 = xv1 * yv1


return
end





#include <stdio.h>

extern int calc_prod ( long, long, double *, double *, double, double, double, double );

int wrap_c_to_Fortran ( long itt,
long npt, // number of observations
double *xxx,
double *yyy,
double xpr,
double xv1,
double yv1,
double pv1 )


// xxx(ip) = ip yyy(ip) = 1. xpr = xpr + xxx(ip) * yyy(ip); ip = 1, npt

// xv1 = 20. yv1 = 30. pv1 = xv1 * yv1

{
short ip;

long npv1;


for(ip=1;ip<=npt;ip++)
printf( "%12.4lf ", xxx[ip] );

for(ip=1;ip<=npt;ip++)
printf( "%12.4lf ", yyy[ip] );

printf( "%12.4lf ", xv1 );

printf( "%12.4lf ", yv1 );


calc_prod ( npt, xxx, yyy, xpr, xv1, yv1, pv1 );


printf( "%12.4lf ", xpr );

printf( "%12.4lf ", pv1 );


// sprintf(szBuff, "\n\nC V means - C V %3ld vs C V %ld", ncvY, ncvX);
// write (itt,'(/ '' XXX * YYY = '', g12.4 )') xpr
// write (itt,'(/ '' XV1 * YV1 = '', g12.4 )') pv1

npv1 = pv1;

return npv1;

}