http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49138
Summary: Add /usr/include/fortran/{,gcc-<version>} to the
file/module search path
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: bur...@gcc.gnu.org
There is a serious lack of a default-searched location for Fortran include
files - and in particular for Fortran .mod files. The latter is particularly
important as different compilers/different versions have different .mod files.
Currently, Linux distributions usually either do not ship .mod files or they
ship them simply in /usr/include.
The /usr/{local/,}include/fortran/ directory should be used (and searched) for
Fortran INCLUDE / #include files.
Module files (or arch-dependent include files) should be searched for in an
compiler/architecture-dependent subdirectory, which can be queried with
-print-mod-dir-suffix:
gfortran $(FFLAGS) -print-mod-dir-suffix
(Note: -m... flags in the $(FFLAGS) might change the result.)
Thus, the search order is:
LOCAL_INCLUDE_DIR/fortran/$(gfortran -print-mod-dir-suffix) # .mod files
LOCAL_INCLUDE_DIR/fortran # include files
LOCAL_INCLUDE_DIR # For backward compatibility
followed by the same order for SYSTEM_INCLUDE_DIR and then STANDARD_INCLUDE_DIR
The result of -print-mod-dir-suffix should be
gcc-<module_version>/lib{,<qual>}
The reason for "lib{,<qual>}" is to allow for architecture-defined directories;
using directly the target (e.g. x86_64-unknown-linux-gnu) instead of the lib
won't work as for x86_64 one can have -m32 and -m64 but target remains the
same, while for i686 and x86_64 -m32, the target changes but the produced
binaries are the same. Additionally, for PowerPC, the default can be 32 or 64
bit.
For the FHS standard tacking, see:
http://bugs.linux-foundation.org/show_bug.cgi?id=757
(The proposal was discussed with Jakub, Richard and Matthias.)
