[PATCH 1/2] New macro AC_FC_MODULE_EXTENSION: Fortran 90 module extension.

[Ralf Wildenhues]

* lib/autoconf/fortran.m4 (AC_FC_MODULE_EXTENSION): New macro,
rewritten from the AX_F90_MODULE_EXTENSION macro from the
Autoconf Macro Archive by Luc Maisonobe and Alexander Pletzer.
* doc/autoconf.texi (Fortran Compiler): Document it.
* tests/local.at (_AT_CHECK_ENV): Do not complain about
FC_MODEXT setting.
* THANKS: Update.
---
 ChangeLog               |   13 +++++++++++++
 doc/autoconf.texi       |   33 +++++++++++++++++++++++++++++++++
 lib/autoconf/fortran.m4 |   35 +++++++++++++++++++++++++++++++++++
 tests/local.at          |    3 ++-
 4 files changed, 83 insertions(+), 1 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ed4c467..9570ce7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,16 @@
+2011-03-06  Luc Maisonobe <...>
+           Alexander Pletzer <...>
+           Ralf Wildenhues  <...>
+
+       New macro AC_FC_MODULE_EXTENSION: Fortran 90 module extension.
+       * lib/autoconf/fortran.m4 (AC_FC_MODULE_EXTENSION): New macro,
+       rewritten from the AX_F90_MODULE_EXTENSION macro from the
+       Autoconf Macro Archive by Luc Maisonobe and Alexander Pletzer.
+       * doc/autoconf.texi (Fortran Compiler): Document it.
+       * tests/local.at (_AT_CHECK_ENV): Do not complain about
+       FC_MODEXT setting.
+       * THANKS: Update.
+
 2011-03-05  Ralf Wildenhues  <address@hidden>
 
        Fix Cray Fortran flag for AC_FC_IMPLICIT_NONE.
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index b552883..f3a87d1 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -8345,6 +8345,39 @@ Fortran Compiler
 variables, respectively.
 @end defmac
 
address@hidden AC_FC_MODULE_EXTENSION
address@hidden
address@hidden fc_module_ext
address@hidden FC_MODEXT
+
+Find the Fortran 90 module file name extension.  Most Fortran 90
+compilers store module information in files separate from the object
+files.  The module files are usually named after the name of the module
+rather than the source file name, with characters possibly turned to
+upper case, plus an extension, often @file{.mod}.
+
+Not all compilers use module files at all, or by default.  The Cray
+Fortran compiler requires @option{-e m} in order to store and search
+module information in @file{.mod} files rather than in object files.
+Likewise, the Fujitsu Fortran compilers uses the @option{-Am} option to
+indicate how module information is stored.
+
+The @code{AC_FC_MODULE_EXTENSION} macro computes the module extension
+without the leading dot, and stores that in the @code{FC_MODEXT}
+variable.  If the compiler does not produce module files, or the
+extension cannot be determined, @code{FC_MODEXT} is empty.  Typically,
+the result of this macro may be used in cleanup @command{make} rules as
+follows:
+
address@hidden
+clean-modules:
+        -test -z "$(FC_MODEXT)" || rm -f *.$(FC_MODEXT)
address@hidden example
+
+The extension, or @samp{unknown}, is cached in the
address@hidden variable.
address@hidden defmac
+
 
 @node Go Compiler
 @subsection Go Compiler Characteristics
diff --git a/lib/autoconf/fortran.m4 b/lib/autoconf/fortran.m4
index 84f3162..864fcaa 100644
--- a/lib/autoconf/fortran.m4
+++ b/lib/autoconf/fortran.m4
@@ -1524,3 +1524,38 @@ AC_DEFUN([AC_FC_IMPLICIT_NONE],
 _AC_FC_IMPLICIT_NONE($@)
 AC_LANG_POP([Fortran])dnl
 ])# AC_FC_IMPLICIT_NONE
+
+
+# AC_FC_MODULE_EXTENSION
+# ----------------------
+# Find the Fortran 90 module file extension.  The module extension is stored
+# in the variable FC_MODEXT and empty if it cannot be determined.  The result
+# or "unknown" is cached in the cache variable ac_cv_fc_module_ext.
+AC_DEFUN([AC_FC_MODULE_EXTENSION],
+[AC_CACHE_CHECK([Fortran 90 module extension], [ac_cv_fc_module_ext],
+[AC_LANG_PUSH(Fortran)
+mkdir conftest.dir
+cd conftest.dir
+ac_cv_fc_module_ext=unknown
+AC_COMPILE_IFELSE([[
+      module conftest_module
+      contains
+      subroutine conftest_routine
+      write(*,'(a)') 'gotcha!'
+      end subroutine
+      end module]],
+  [ac_cv_fc_module_ext=`ls | sed -n 's,conftest_module\.,,p'`
+   if test x$ac_cv_fc_module_ext = x; then
+dnl Some F90 compilers use upper case characters for the module file name.
+     ac_cv_fc_module_ext=`ls | sed -n 's,CONFTEST_MODULE\.,,p'`
+   fi])
+cd ..
+rm -rf conftest.dir
+AC_LANG_POP(Fortran)
+])
+FC_MODEXT=$ac_cv_fc_module_ext
+if test "$FC_MODEXT" = unknown; then
+  FC_MODEXT=
+fi
+AC_SUBST([FC_MODEXT])dnl
+])
diff --git a/tests/local.at b/tests/local.at
index bfd124f..e08d8b1 100644
--- a/tests/local.at
+++ b/tests/local.at
@@ -317,7 +317,7 @@ if test -f state-env.before && test -f state-env.after; then
       [cross_compiling|U],
       [interpval|PATH_SEPARATOR],
       [F77_DUMMY_MAIN|f77_(case|underscore)],
-      [FC(_DUMMY_MAIN|FLAGS|LIBS|FLAGS_f)?],
+      [FC(_DUMMY_MAIN|FLAGS|LIBS|FLAGS_f|_MODEXT)?],
       [ALLOCA|GETLOADAVG_LIBS|KMEM_GROUP|NEED_SETGID|POW_LIB],
       [AWK|LEX|LEXLIB|LEX_OUTPUT_ROOT|LN_S|M4|MKDIR_P|RANLIB|SET_MAKE|YACC],
       [GREP|[EF]GREP|SED],
@@ -368,6 +368,7 @@ do
        /^m4_defn([m4_re_word])=./ !d
        /^[[^=]]*='\'''\''$/ d
        /^a[[cs]]_/ d
+       /^OLDPWD=/ d
        /^PPID=/ d
        /^RANDOM=/ d
        /^SECONDS=/ d
-- 
1.7.4.1.203.g07873