As of this week, the Fortran documentation tool Fordocu is available as Open Source on sourceforge.net. The tool has been developed by VORtech by order of the Netherlands Environmental Assessment Agency (PBL, in Dutch). PBL has kindly made the tool available for the Fortran developer community.

Fordocu analyses a Fortran program (and the subroutines and functions that belong to it), taking the comments in the code into account. Based on this information, the tool generates a number of overviews that are conveniently bundled in an html interface. The overviews provide information about the call tree, about where each subroutine is used, and with what arguments, and gives the meaning of variables, subroutines, functions and modules (as far as can be determined from the comments in the code).

More information can be found here. Fordocu can be download here.