NAME

       ExtUtils::F77 - Simple interface to F77 libs

DESCRIPTION

       This module tries to figure out how to link C programs with Fortran subroutines on your
       system. Basically one must add a list of Fortran runtime libraries. The problem is their
       location and name varies with each OS/compiler combination! It was originally developed to
       make building and installation of the PGPLOT module easier, which links to the pgplot
       Fortran graphics library. It is now used by a number of perl modules.

       This module tries to implement a simple 'rule-of-thumb' database for various flavours of
       UNIX systems.  A simple self-documenting Perl database of knowledge/code for figuring out
       how to link for various combinations of OS and compiler is embedded in the modules Perl
       code. Please help save the world by submitted patches for new database entries for your
       system at <https://github.com/PDLPorters/extutils-f77>

       Note the default on most systems is now to search for a generic 'GNU' compiler which can
       be gfortran, g77, g95 or fort77 (in that order based on usage) and then find the
       appropriate link libraries automatically. (This is the 'Generic' 'GNU' database entry in
       the code.)

       The target compiler can be explicitly overriden by setting the environment variable F77,
       e.g.

        % setenv F77 "x86_64-pc-linux-gnu-gfortran"
        % perl -MExtUtils::F77 -e 'print ExtUtils::F77->compiler, "\n"'

       The library list which the module returns can be explicitly overridden by setting the
       environment variable F77LIBS, e.g.

         % setenv F77LIBS "-lfoo -lbar"
         % perl -MExtUtils::F77 -e 'print ExtUtils::F77->runtime, "\n"'
         ...

SYNOPSIS

         use ExtUtils::F77;               # Automatic guess
         use ExtUtils::F77 qw(sunos);     # Specify system
         use ExtUtils::F77 qw(linux g77); # Specify system and compiler
         $fortranlibs = ExtUtils::F77->runtime;

METHODS

       The following are all class methods.

   runtime
       Returns a list of F77 runtime libraries.

         $fortranlibs = ExtUtils::F77->runtime;

   runtimeok
       Returns TRUE only if runtime libraries have been found successfully.

   trail_
       Returns true if F77 names have trailing underscores.

   compiler
       Returns command to execute the compiler (e.g. 'f77').

   cflags
       Returns compiler flags.

   testcompiler
       Test to see if compiler actually works.

DEBUGGING

       To debug this module, and/or get more information about its workings, set
       $ExtUtils::F77::DEBUG to a true value. If set, it will "warn" various information about
       its operations.

       As of version 1.22, this module will no longer print or warn if it is working normally.

SEE ALSO

       PDL (PDL::Minuit and PDL::Slatec), PGPLOT

AUTHOR

       Karl Glazebrook, with many other contributions (see git repository at
       https://github.com/PDLPorters/extutils-f77)