Am 25.11.20 um 23:02 schrieb Maciej W. Rozycki:
The Fortran intrinsis like HUGE, EPSILON, SELECTED_REAL_KIND etc
would have to be handled correctly, both for simplification in
the front end and in the library.
Does the program
print *,HUGE(1.0)
print *,EPSILON(1.0)
end
print correct values?
Well, it does not link, for the somewhat unsurprising reason of a missing
libgfortran runtime.
OK.
What you can do instead is to use the C interpoerability feature
to make a Fortran subroutine which does not depend on
libgfortran, like this:
subroutine read_val (r, d, i) bind(c)
use iso_c_binding, only : c_float, c_double, c_int
real(kind=c_float), intent(out) :: r
real(kind=c_double), intent(out) :: d
integer(kind=c_int), intent(out) :: i
r = huge(1._c_float)
d = huge(1._c_double)
i = selected_real_kind(6)
end subroutine read_val
and then call it from C, like this:
#include <stdio.h>
void read_val (float *, double *, int *);
int main ()
{
float r;
double d;
int i;
read_val (&r, &d, &i);
printf ("r = %e d = %e i = %d\n", r, d, i);
return 0;
}
On my (IEEE) box, this prints
r = 3.402823e+38 d = 1.797693e+308 i = 4
so if you have a working printf (or some other way to display
floating-point-variables) for C, you can examine the
values.
Best regards
Thomas
