As has been discussed for a long time, decided in the December 2012

meeting, and RFCed in mid-December (#3424): we no longer build the MPI
C++ bindings by default.

The C++ bindings are still ''there'' -- starting with 1.9, we'll just
be providing a little encouragement to no longer use them.

There are no definite plans to ''remove'' the C++ bindings yet.  At
the earliest, we would remove them in the next feature series after
1.9. 

This commit was SVN r27755.

README

@@ -1071,10 +1071,14 @@ MPI FUNCTIONALITY
   not enable MPI_THREAD_MULTIPLE - see above option for that feature.
   This is currently disabled by default.
 
---disable-mpi-cxx
-  Disable building the C++ MPI bindings.  Note that this does *not*
-  disable the C++ checks during configure; some of Open MPI's tools
-  are written in C++ and therefore require a C++ compiler to be built.
+--enable-mpi-cxx
+  Enable building the C++ MPI bindings.  The MPI C++ bindings were
+  deprecated in MPI-2.2 and deleted in MPI-3.0.  Open MPI no longer
+  builds its C++ bindings by default.  It is likely that the C++
+  binding will be removed from Open MPI at some point in the future.
+
+  Note that disabling building the C++ bindings does *not* disable all
+  C++ checks during configure.
 
 --disable-mpi-fortran
   Disable building the Fortran MPI bindings.

config/ompi_configure_options.m4

@@ -142,8 +142,8 @@ AC_SUBST(MPIF_H_PMPI_W_FUNCS)
 AC_MSG_CHECKING([if want C++ bindings])
 AC_ARG_ENABLE(mpi-cxx,
     AC_HELP_STRING([--enable-mpi-cxx],
-                   [enable C++ MPI bindings (default: enabled)]))
-if test "$enable_mpi_cxx" != "no"; then
+                   [enable C++ MPI bindings (default: disabled)]))
+if test "$enable_mpi_cxx" = "yes"; then
     AC_MSG_RESULT([yes])
     WANT_MPI_CXX_SUPPORT=1
 else