This tool can either rebuild the declarative part of a Fortran program unit declaring all names or alternatively add declarations for all implicitly typed names.
Name means a variable, common block, function or subroutine, parameter name etc.
If none of these options is used, or if the output file would overwrite the input file, the input file is backed up to infile .original and the output file replaces the input file. It follows the input filename to which it applies. This option cannot be used with wildcard filenames. Specifies characters to be prepended to the base name of the input file in order to generate the output file name. This mode is the default.