Calling C from FORTRAN under Unix

[Charles Packer]

On a Unix system I want to call a C routine from a FORTRAN
program. The linker says the C routine is undefined.  On a VMS
system, the problem doesn't happen. The reason why there is a
problem on a Unix system has something to do with the name of
the C subroutine acquiring a preceding underscore ("_") during
compilation, or some such nonsense. To anyone familiar with this
problem: what is the way around it?