Tutorial: Using C/C++ and Fortran together

http://www.yolinux.com/TUTORIALS/LinuxTutorialMixingFortranAndC.html

This tutorial covers mixing C/C and FORTRAN together, allowing C/C to call FORTRAN functions and FORTRAN to call C/C functions. Integrating C/C and FORTRAN into a single executable relies upon knowing how to interface the function calls, argument list and global data structures so the symbols match in the object code during linking