Ubuntu Manpage: dh_fortran_mod - Install Fortran 90 .mod files and add dependency information.

NAME

       dh_fortran_mod - Install Fortran 90 .mod files and add dependency information.

SYNOPSIS

       dh_fortran_mod   [--sourcedir=dir] [$<debhelper options>]

DESCRIPTION

       dh_fortran_mod is a debhelper program that finds Fortran module and submodule files and adds dependencies
       to gfortran-$version as required to the package using via the variable ${misc:Depends}.

       dh_fortran_mod is expected to be automatically added using the debhelper "addon" fortran_mod ie. using
       the debian/rules line:

           dh $@ --with fortran_mod

       dh_fortran_modSearches the debian/ directory for files debian/pkg.fortran-mod$ which list module files to
       include, with the same syntax as debhelper install files.

OPTIONS

       --sourcedir=dir
           Look in the specified directory for files to be installed.

           Typically Fortran module files are included in library development packages.

TODO

dh_fortran_mod will be expanded to find mod files automatically from the debian/tmp directory. It
will enable the installation of mod files in parallel for multiple compilers. It will install .smod
files for Fortran 2018.

The fortran-mod file syntax follows dh_install: pairs of sources and optional target directories.
The default directory will be $fmoddir ( /usr/lib/$multiarch/fortran/$compiler_mod_directory/) If the
target directory is absolute (starts with a '/'), this directory is used in the target package. If
the target does not absolute, it will be treated as a subdirectory of $fmoddir.

$compiler_mod_directory is based on the compiler module version: currently gfortran-mod-15 for
gfortran-9, and flang-mod-34 for flang-7. These will be updated for incompatible compiler versions.
There is a symlink in $libdir/fortran/ for the 'canonical' compiler name, linking to this, e.g.
/usr/lib/$multiarch/fortran/x86_64-linux-gnu-gfortran-9 -> gfortran-mod-15 This enables makefile
fragments to construct $fmoddir as required from :

FC:=$(shell basename $(shell readlink -f /usr/bin/gfortran))
FMODDIR:=/usr/lib/$(shell dpkg-architecture -qDEB_HOST_MULTIARCH)/fortran/$(FC)

Its not clear what happens on module version changes in Flang/F18. While the version number signifies
format changes, it appears the design is currently to be backward compatible and read previous
versions. Hence symlinks for flang handling may be required; however a new f18 front-end is being
developed, so this may change.

AUTHORS