Porting UNIX Fortran Source to Win32

Most Fortran migrations are a port, not a rewrite, to Win32. However, Fortran migrations involve the migration and integration of the other language modulesin the application. Techniques and strategies for using C and C++ tools and source from Fortran are needed to complete the application migration.

As a result, most of the discussion in this section focuses on how to integrate Fortran code with C and C++ modules or libraries on the Windows platform.

Using C/C++ Libraries or Fortran Modules

Fortran applications can access cross-platform libraries either by using C and C++ libraries, or through Fortran modules (available with Fortran 90 and later versions). If the cross-platform libraries are written in C or C++, there is little (if any) difference between this type of strategy and a port to Win32 strategy. Currently, there are nota large number of third-party Fortran module suppliers. This is due to the limited market for Fortran and the fact that Fortran compilers are provided by third parties. Microsoft does not provide a Fortran compiler. Fortran modules are typically supplied by the compiler vendor or are created in house.

Porting Fortran to Windows

Finally, it is possible to rewrite an application written entirely in Fortran to target Windows. The key task here is to identify how platform-specific features are implemented in Fortran. This is typically done with Fortran modules. If this isthe case, you must identify or develop a corresponding Fortran module for each feature on Windows that exists on the source platform. For example, if an OpenGL module and threading module are used on UNIX, you need to identify or develop a corresponding OpenGL and threading module to use on Windows.