Re: Fortran wrappers

[Andy May]

Many thanks both for the suggestions.

Jeff: it doesn't cause any problems, it's just makes a longer configure
script and puts CC and CFLAGS under the list of 'influential environment
variables' for configure's help. I thought it worth mentioning as a
potential enhancement, perhaps to use the currently selected language,
defaulting to C if the current language is not appropriate. Probably I'll
use something based on what you attached, perhaps automatically generated
by applying some sed to fortran.m4 so that any updates in the future to
fortran.m4 are brought in.

Best wishes,

Andy

On 19 May 2017 at 18:06, Daily, Jeff A <address@hidden> wrote:

> >    We have a project which is comprised of Fortran and C++ code, linked
>
> >    together at the end with the C++ compiler. I have configure setup
>
> >    with AC_LANG([C++]), and push/pop to Fortran as required. I notice
> that
>
> >    using AC_FC_WRAPPERS() results in configure containing all the extra
>
> >    infrastructure for C compilation and those tests use CC and CFLAGS.
>
> >
>
> >    Looking at fortran.m4 I see the reason is there are a few instances of
>
> >    explicitly using the C compiler. Would it somehow be possible via an
> extra
>
> >    argument or otherwise to add the ability to instruct those macros to
> use
>
> >    the C++ compiler instead?
>
>
>
> Is it causing problems to have the C infrastructure within the Makefile?
> Or are you simply hoping for a cleaner, stripped-down Makefile?
>
>
>
> If you’re worried about the C compiler configure checks automatically
> testing for headers, etc., just make sure you test for the same features
> with the C++ compiler first and those C tests should (I think) get skipped
> since the results were already provided using the C++ compiler.
>
>
>
> Looks like the Fortran tests that trigger a C compiler are:
>
> _AC_FC_DUMMY_MAIN
>
> _AC_FC_MAIN
>
> __AC_FC_NAME_MANGLING
>
>
>
> And _AC_FC_DUMMY_MAIN is required by AC_FC_WRAPPERS, eventually.
>
>
>
> Though not ideal, you could write your own name mangling configure test
> and substitute the C++ compiler.  I’ve attached a file
> “my_fc_name_mangling.m4” that does just that.  Not sure it’ll make it to
> the autoconf list as an attachment, so I’ll copy and paste below.  I’ve
> renamed the various __AC_* and _AC_* and AC_* macros to “MY”, commented out
> the required call to _AC_FC_DUMMY_MAIN (YMMV whether you need that, but
> I’ll require a C compile again), and substituted the C++ compiler within
> the name mangling test code.  Place that file wherever your ACLOCAL_AMFLAGS
> variable in the top of your Makefile.am points to so that autoreconf will
> pick it up.  Use “MY_FC_NAME_MANGLING” – or the F77 one – in your
> configure.ac file.
>
>
>
>
>
> File: my_fc_name_mangling.m4
>
>
>
> # This file was copied and modified from Autoconf.  Original license
>
> # information appears below.
>
>
>
> # This file is part of Autoconf.                       -*- Autoconf -*-
>
> # Fortran languages support.
>
> # Copyright (C) 2001, 2003-2012 Free Software Foundation, Inc.
>
>
>
> # This file is part of Autoconf.  This program is free
>
> # software; you can redistribute it and/or modify it under the
>
> # terms of the GNU General Public License as published by the
>
> # Free Software Foundation, either version 3 of the License, or
>
> # (at your option) any later version.
>
> #
>
> # This program is distributed in the hope that it will be useful,
>
> # but WITHOUT ANY WARRANTY; without even the implied warranty of
>
> # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>
> # GNU General Public License for more details.
>
> #
>
> # Under Section 7 of GPL version 3, you are granted additional
>
> # permissions described in the Autoconf Configure Script Exception,
>
> # version 3.0, as published by the Free Software Foundation.
>
> #
>
> # You should have received a copy of the GNU General Public License
>
> # and a copy of the Autoconf Configure Script Exception along with
>
> # this program; see the files COPYINGv3 and COPYING.EXCEPTION
>
> # respectively.  If not, see <http://www.gnu.org/licenses/>.
>
>
>
> # Written by David MacKenzie, with help from
>
> # Franc,ois Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
>
> # Roland McGrath, Noah Friedman, david d zuhn, and many others.
>
>
>
> # __MY_FC_NAME_MANGLING
>
> # ---------------------
>
> # Test for the name mangling scheme used by the Fortran compiler.
>
> #
>
> # Sets ac_cv_{f77,fc}_mangling. The value contains three fields, separated
>
> # by commas:
>
> #
>
> # lower case / upper case:
>
> #    case translation of the Fortran symbols
>
> # underscore / no underscore:
>
> #    whether the compiler appends "_" to symbol names
>
> # extra underscore / no extra underscore:
>
> #    whether the compiler appends an extra "_" to symbol names already
>
> #    containing at least one underscore
>
> #
>
> AC_DEFUN([__MY_FC_NAME_MANGLING],
>
> [_AC_FORTRAN_ASSERT()dnl
>
> AC_CACHE_CHECK([for _AC_LANG name-mangling scheme],
>
>             ac_cv_[]_AC_LANG_ABBREV[]_mangling,
>
> [AC_COMPILE_IFELSE(
>
> [[      subroutine foobar()
>
>       return
>
>       end
>
>       subroutine foo_bar()
>
>       return
>
>       end]],
>
> [mv conftest.$ac_objext cfortran_test.$ac_objext
>
>
>
>   ac_save_LIBS=$LIBS
>
>   LIBS="cfortran_test.$ac_objext $LIBS $[]_AC_LANG_PREFIX[]LIBS"
>
>
>
>   AC_LANG_PUSH(C++)dnl
>
>   ac_success=no
>
>   for ac_foobar in foobar FOOBAR; do
>
>     for ac_underscore in "" "_"; do
>
>       ac_func="$ac_foobar$ac_underscore"
>
>       AC_LINK_IFELSE([AC_LANG_CALL([], [$ac_func])],
>
>                 [ac_success=yes; break 2])
>
>     done
>
>   done
>
>   AC_LANG_POP(C++)dnl
>
>
>
>   if test "$ac_success" = "yes"; then
>
>      case $ac_foobar in
>
>       foobar)
>
>         ac_case=lower
>
>         ac_foo_bar=foo_bar
>
>         ;;
>
>       FOOBAR)
>
>         ac_case=upper
>
>         ac_foo_bar=FOO_BAR
>
>         ;;
>
>      esac
>
>
>
>      AC_LANG_PUSH(C++)dnl
>
>      ac_success_extra=no
>
>      for ac_extra in "" "_"; do
>
>       ac_func="$ac_foo_bar$ac_underscore$ac_extra"
>
>       AC_LINK_IFELSE([AC_LANG_CALL([], [$ac_func])],
>
>                   [ac_success_extra=yes; break])
>
>      done
>
>      AC_LANG_POP(C++)dnl
>
>
>
>      if test "$ac_success_extra" = "yes"; then
>
>       ac_cv_[]_AC_LANG_ABBREV[]_mangling="$ac_case case"
>
>       if test -z "$ac_underscore"; then
>
>         
> ac_cv_[]_AC_LANG_ABBREV[]_mangling="$ac_cv_[]_AC_LANG_ABBREV[]_mangling,
> no underscore"
>
>       else
>
>         
> ac_cv_[]_AC_LANG_ABBREV[]_mangling="$ac_cv_[]_AC_LANG_ABBREV[]_mangling,
> underscore"
>
>       fi
>
>       if test -z "$ac_extra"; then
>
>         
> ac_cv_[]_AC_LANG_ABBREV[]_mangling="$ac_cv_[]_AC_LANG_ABBREV[]_mangling,
> no extra underscore"
>
>       else
>
>         
> ac_cv_[]_AC_LANG_ABBREV[]_mangling="$ac_cv_[]_AC_LANG_ABBREV[]_mangling,
> extra underscore"
>
>       fi
>
>       else
>
>       ac_cv_[]_AC_LANG_ABBREV[]_mangling="unknown"
>
>       fi
>
>   else
>
>      ac_cv_[]_AC_LANG_ABBREV[]_mangling="unknown"
>
>   fi
>
>
>
>   LIBS=$ac_save_LIBS
>
>   rm -rf conftest*
>
>   rm -f cfortran_test*],
>
>   [AC_MSG_FAILURE([cannot compile a simple Fortran program])])
>
> ])
>
> ])# __MY_FC_NAME_MANGLING
>
>
>
>
>
> # The replacement is empty.
>
> AU_DEFUN([AC_F77_NAME_MANGLING], [])
>
>
>
>
>
> # _MY_F77_NAME_MANGLING
>
> # ---------------------
>
> AC_DEFUN([_MY_F77_NAME_MANGLING],
>
> [AC_REQUIRE([AC_F77_LIBRARY_LDFLAGS])dnl
>
> dnl AC_REQUIRE([AC_F77_DUMMY_MAIN])dnl
>
> AC_LANG_PUSH(Fortran 77)dnl
>
> __MY_FC_NAME_MANGLING
>
> AC_LANG_POP(Fortran 77)dnl
>
> ])# _MY_F77_NAME_MANGLING
>
>
>
>
>
> # _MY_FC_NAME_MANGLING
>
> # --------------------
>
> AC_DEFUN([_MY_FC_NAME_MANGLING],
>
> [AC_REQUIRE([AC_FC_LIBRARY_LDFLAGS])dnl
>
> dnl AC_REQUIRE([AC_FC_DUMMY_MAIN])dnl
>
> AC_LANG_PUSH(Fortran)dnl
>
> __MY_FC_NAME_MANGLING
>
> AC_LANG_POP(Fortran)dnl
>
> ])# _MY_FC_NAME_MANGLING
>
>
>
>
>
> # _MY_FC_WRAPPERS
>
> # ---------------
>
> # Defines C macros {F77,FC}_FUNC(name,NAME) and {F77,FC}_FUNC_(name,NAME)
> to
>
> # properly mangle the names of C identifiers, and C identifiers with
>
> # underscores, respectively, so that they match the name mangling
>
> # scheme used by the Fortran compiler.
>
> AC_DEFUN([_MY_FC_WRAPPERS],
>
> [_AC_FORTRAN_ASSERT()dnl
>
> AH_TEMPLATE(_AC_FC[_FUNC],
>
>     [Define to a macro mangling the given C identifier (in lower and upper
>
>      case), which must not contain underscores, for linking with
> Fortran.])dnl
>
> AH_TEMPLATE(_AC_FC[_FUNC_],
>
>     [As ]_AC_FC[_FUNC, but for C identifiers containing underscores.])dnl
>
> case $ac_cv_[]_AC_LANG_ABBREV[]_mangling in
>
>   "lower case, no underscore, no extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [name])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [name]) ;;
>
>   "lower case, no underscore, extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [name])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [name [##] _]) ;;
>
>   "lower case, underscore, no extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [name [##] _])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [name [##] _]) ;;
>
>   "lower case, underscore, extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [name [##] _])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [name [##] __]) ;;
>
>   "upper case, no underscore, no extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [NAME])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [NAME]) ;;
>
>   "upper case, no underscore, extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [NAME])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [NAME [##] _]) ;;
>
>   "upper case, underscore, no extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [NAME [##] _])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [NAME [##] _]) ;;
>
>   "upper case, underscore, extra underscore")
>
>         AC_DEFINE(_AC_FC[_FUNC(name,NAME)],  [NAME [##] _])
>
>         AC_DEFINE(_AC_FC[_FUNC_(name,NAME)], [NAME [##] __]) ;;
>
>   *)
>
>         AC_MSG_WARN([unknown Fortran name-mangling scheme])
>
>         ;;
>
> esac
>
> ])# _MY_FC_WRAPPERS
>
>
>
>
>
> # MY_F77_WRAPPERS
>
> # ---------------
>
> AC_DEFUN([MY_F77_WRAPPERS],
>
> [AC_REQUIRE([_MY_F77_NAME_MANGLING])dnl
>
> AC_LANG_PUSH(Fortran 77)dnl
>
> _MY_FC_WRAPPERS
>
> AC_LANG_POP(Fortran 77)dnl
>
> ])# MY_F77_WRAPPERS
>
>
>
>
>
> # MY_FC_WRAPPERS
>
> # --------------
>
> AC_DEFUN([MY_FC_WRAPPERS],
>
> [AC_REQUIRE([_MY_FC_NAME_MANGLING])dnl
>
> AC_LANG_PUSH(Fortran)dnl
>
> _MY_FC_WRAPPERS
>
> AC_LANG_POP(Fortran)dnl
>
> ])# MY_FC_WRAPPERS
>
>
>