chris@umcp-cs.UUCP (04/05/84)
In *.*BSD (and probably therefore System *), if you want to
call a C subroutine from F77 code, write the C subroutine normally,
but change parameter types:
f77 type C type
-------- ------
integer int *
integer*2 short *
real*4 float *
real*8 double *
complex*8 struct complex *
complex*16 struct dcomplex *
struct complex { float re, im; };
struct dcomplex { double re, im; };
Also, if the f77 routine wants to call "foo", name the C routine
"foo_".
Return values should just be return'ed (with the appropriate type)
in the case of integer and real*8. I'm not sure about the others.
Example:
program test
integer i, j
integer function cfunc
do 10 i = 1, 100
j = cfunc (i)
10 continue
end
int
cfunc_ (i)
int *i;
{
<whatever>;
return retval;
}
--------
To call Fortran routines from Pascal is considerably more difficult,
because Pascal won't let you use "_" in identifiers. (#@%^*$&) One
method is to use a C interface routine:
to call f77 function "func" from pascal:
integer function func (i, j, k)
integer i, j, k
...
return
end
int
xfunc (i, j, k) /* x-ecute f77 "func" */
int *i, *j, *k;
{
return func_ (i, j, k);
}
{ I'm rather rusty on Pascal; ignore minor syntactic mistakes }
function xfunc (var i, j, k : integer) : integer external;
program prog (input, output);
begin
...
xfunc (...);
...
end.
Note also that if you don't want the hassle of providing "var" parameters,
you can have your C code written like this:
int
xfunc (i, j, k)
int i, j, k;
{
return func_ (&i, &j, &k);
}
This implies that even if the Fortran function modifies its parameters,
it can't affect the Pascal values.
Chris
--
In-Real-Life: Chris Torek, Univ of MD Comp Sci
UUCP: {seismo,allegra,brl-bmd}!umcp-cs!chris
CSNet: chris@umcp-cs ARPA: chris.umcp-cs@CSNet-Relay