Most users of g77 can be divided into two camps:
Users writing new code generally understand most of the necessary
aspects of Fortran to write “mainstream” code, but often need
help deciding how to handle problems, such as the construction
of libraries containing
Users dealing with “legacy” code sometimes don't have much experience with Fortran, but believe that the code they're compiling already works when compiled by other compilers (and might not understand why, as is sometimes the case, it doesn't work when compiled by g77).
The following information is designed to help users do a better job coping with existing, “legacy” Fortran code, and with writing new code as well.