Fortran DLLs

Fortran subroutines that will be called from Visual Basic must reside in Dynamic Link Library (DLL) files. There is no other effective way around this. A DLL can contain one, but more frequently several, Fortran procedure(s). The compiler switches and procedure declarations used to create a DLL are highly variable; each Fortran compiler vendor has its own way. Although in the next sections we explain the very basics of how to create DLLs with different compilers, you should become familiar with the options and switches used by your specific Fortran compiler, and thoroughly study your compiler documentation on this topic.

Calling conventions