It appears that most versions of the IBM XL compiler (including the latest

releases on Linux and OS X) don't handle const_cast<> of 2-dimensional 
arrays properly.  If we're using one of the compilers that isn't friendly
to such casts, fall back to a standard C-style cast.

refs: #271

This commit was SVN r11263.

config/ompi_setup_cxx.m4

@@ -183,6 +183,28 @@ AC_DEFUN([OMPI_SETUP_CXX],[
         ;;
     esac
 
+    # see if the compiler supports const_cast of 2-dimensional arrays
+    AC_LANG_PUSH(C++)
+    AC_CACHE_CHECK([if $CXX supports const_cast<> properly],
+       [ompi_cv_cxx_supports_2d_const_cast],
+       [AC_TRY_COMPILE([int non_const_func(int ranges[][3]);
+int cast_test(const int ranges[][3]) {
+  return non_const_func(const_cast<int(*)[3]>(ranges));  
+}],
+            [],
+            [ompi_cv_cxx_supports_2d_const_cast="yes"],
+            [ompi_cv_cxx_supports_2d_const_cast="no"])])
+    if test "$ompi_cv_cxx_supports_2d_const_cast" = "yes" ; then
+        use_2d_const_cast=1
+    else
+        use_2d_const_cast=0
+    fi
+    AC_DEFINE_UNQUOTED([OMPI_CXX_SUPPORTS_2D_CONST_CAST],
+                       [$use_2d_const_cast],
+                       [Whether a const_cast on a 2-d array will work with the C++ compiler])
+    unset use_2d_const_cast
+    AC_LANG_POP(C++)
+
     # Note: gcc-imperonating compilers accept -O3
     if test "$WANT_DEBUG" = "1"; then
         OPTFLAGS=

ompi/include/mpi.h.in

@@ -74,6 +74,9 @@
 /* Whether we want MPI cxx support or not */
 #undef OMPI_WANT_CXX_BINDINGS
 
+/* Whether a const_cast on a 2-d array will work with the C++ compiler */
+#undef OMPI_CXX_SUPPORTS_2D_CONST_CAST
+
 /* Whether we want the MPI f77 bindings or not */
 #undef OMPI_WANT_F77_BINDINGS
 

ompi/mpi/cxx/group_inln.h

@@ -97,7 +97,13 @@ inline MPI::Group
 MPI::Group::Range_incl(int n, const int ranges[][3]) const
 {
   MPI_Group newgroup;
-  (void)MPI_Group_range_incl(mpi_group, n, const_cast<int(*)[3]>(ranges), &newgroup);
+  (void)MPI_Group_range_incl(mpi_group, n,
+#if OMPI_CXX_SUPPORTS_2D_CONST_CAST
+                             const_cast<int(*)[3]>(ranges), 
+#else
+                             (int(*)[3]) ranges,
+#endif
+                             &newgroup);
   return newgroup;
 }
 
@@ -105,7 +111,13 @@ inline MPI::Group
 MPI::Group::Range_excl(int n, const int ranges[][3]) const
 {
   MPI_Group newgroup;
-  (void)MPI_Group_range_excl(mpi_group, n, const_cast<int(*)[3]>(ranges), &newgroup);
+  (void)MPI_Group_range_excl(mpi_group, n,
+#if OMPI_CXX_SUPPORTS_2D_CONST_CAST
+                             const_cast<int(*)[3]>(ranges),
+#else
+                             (int(*)[3]) ranges,
+#endif
+                             &newgroup);
   return newgroup;
 }