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openmpi/examples/hello_cxx.cc
Jeff Squyres a4378a6643 Re-define the order of #includes because MPI's C++ bindings
unfortunately redefined some C library constants (SEEK_SET, SEEK_CUR,
SEEK_END).  Scheesh -- who designed those bindings, anyway?

Most <stdio.h>'s and <iostream>'s are sane enough that if those values
are already #define'd, they won't redefine them.  So various other
MPI's out there have counseled that if you want to compile with the
C++ MPI bindings, ensure to include "mpi.h" before <iostream> or
<stdio.h> (in C++ source files).

This commit was SVN r11511.
2006-08-31 18:16:27 +00:00

32 строки
1021 B
C++

//
// Copyright (c) 2004-2006 The Trustees of Indiana University and Indiana
// University Research and Technology
// Corporation. All rights reserved.
// Copyright (c) 2006 Cisco Systems, Inc. All rights reserved.
//
// Sample MPI "hello world" application in C++
//
// MPI's C++ bindings unfortunately redefined some POSIX constants
// (SEEK_SET and friends). Fortunately, most versions of <iostream>
// and <stdio.h> are sane enough that if you include "mpi.h" first,
// they won't redefine the problematic values. Note, however, that
// 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>
int main(int argc, char **argv)
{
int rank, size;
MPI::Init();
rank = MPI::COMM_WORLD.Get_rank();
size = MPI::COMM_WORLD.Get_size();
std::cout << "Hello, world! I am " << rank << " of " << size << std::endl;
MPI::Finalize();
return 0;
}