How I can use MathGL with Fortran?
You can use MathGL as is with gfortran because it use by default AT&T notation for external functions. For other compilers (like, Visual Fortran) you have to switch on AT&T notation manually. The AT&T notation require that symbol ‘_’ is added at the end of function name, function argument(s) is passed by pointers and string length(s) is passed at the end of argument list.