Refs trac:387

* Document --disable-mpi-cxx-seek
 * Document that you need to include "mpi.h" after system-level
   headers that create the SEEK_* constants
 * Make the C++ examples follow this behavior (include "mpi.h" after
   <iostream>)

This commit was SVN r12123.

The following Trac tickets were found above:
  Ticket 387 --> https://svn.open-mpi.org/trac/ompi/ticket/387

README

@@ -278,6 +278,10 @@ base as of this writing (12 Sep 2006):
   interface.  A "large" size that includes the two choice buffer MPI
   functions is possible in future versions of Open MPI.
 
+- MPI::SEEK_* constants are now supported in C++ MPI applications, but
+  only if "mpi.h" is included after system-level header files that
+  define the POSIX SEEK_* constants (such as <stdio.h> or <iostream>).
+
 ===========================================================================
 
 Building Open MPI
@@ -374,6 +378,14 @@ for a full list); a summary of the more commonly used ones follows:
   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.
 
+--disable-mpi-cxx-seek
+  Disable the MPI::SEEK_* constants.  Due to a problem with the MPI-2
+  specification, these constants can conflict with system-level SEEK_*
+  constants.  Open MPI attempts to work around this problem, but the
+  workaround may fail in some esoteric situations.  The
+  --disable-mpi-cxx-seek switch disables Open MPI's workarounds (and
+  therefore the MPI::SEEK_* constants will be unavailable).
+
 --disable-mpi-f77
   Disable building the Fortran 77 MPI bindings.
 

examples/hello_cxx.cc

@@ -14,8 +14,8 @@
 // this means that you should not make calls to fseek(3) (and friends)
 // in a C++ source file that includes <mpi.h>!
 
-#include "mpi.h"
 #include <iostream>
+#include "mpi.h"
 
 int main(int argc, char **argv)
 {

examples/ring_cxx.cc

@@ -14,8 +14,8 @@
 // this means that you should not make calls to fseek(3) (and friends)
 // in a C++ source file that includes <mpi.h>!
 
-#include "mpi.h"
 #include <iostream>
+#include "mpi.h"
 
 int main(int argc, char *argv[])
 {