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openmpi/ompi/mpi/cxx/errhandler.h
Jeff Squyres 0a28212392 This is a workaround to bug in the Intel C++ compiler, version 9.1
(all versions up to and including 20060925).  The issue has been
reported to Intel, along with a small [non-MPI] test program that
reproduces the problem (the test program and the OMPI C++ bindings
work fine with Intel C++ 9.0 and many other C++ compilers).

In short, a static initializer for a global variable (i.e., its
constructor is fired before main()) that takes as an argument a
reference to a typedef'd type will simply get the wrong value in the
argument.  Specifically:

{{{
namespace MPI {
    Intracomm COMM_WORLD(MPI_COMM_WORLD);
}
}}}

The constructor for MPI::Intracomm should get the value of
&ompi_mpi_comm_world.  It does not; it seems to get a random value.

As mandated by MPI-2, annex B.13.4, for C/C++ interoperability, the
prototype for this constructor is:

{{{
class Intracomm {
public:
    Intracomm(const MPI_Comm& data);
};
}}}

Experiments with icpc 9.1/20060925 have shown that removing the
reference from the prototype makes it work (!).  After lots of
discussions about this issue with a C++ expert (Doug Gregor from IU),
we decided the following (cut-n-paste from an e-mail):

-----
> So here's my question: given that OMPI's MPI_<CLASS> types are all
> pointers, is there any legal MPI program that adheres to the above
> bindings that would fail to compile or work properly if we simply
> removed the "&" from the second binding, above?

I don't know of any way that a program could detect this change. FWIW,
the C++ committee has agreed that implementation of the C++ standard
library are allowed to decide arbitrarily between const& and by-value.
If they don't care, MPI users won't care.

When you remove the '&', I suggest also removing the "const". It is
redundant, but can trigger some strange name mangling in Sun's C++
compiler.
-----

So with this change:

 * we now work again with the Intel 9.1 compiler
 * our C++ bindings do not exactly conform to the MPI-2 spec, but
   valid/legal MPI C++ apps cannot tell the difference (i.e., the
   functionality is the same)

This commit was SVN r12514.
2006-11-09 17:34:12 +00:00

144 строки
3.8 KiB
C++

// -*- c++ -*-
//
// Copyright (c) 2004-2005 The Trustees of Indiana University and Indiana
// University Research and Technology
// Corporation. All rights reserved.
// Copyright (c) 2004-2005 The University of Tennessee and The University
// of Tennessee Research Foundation. All rights
// reserved.
// Copyright (c) 2004-2005 High Performance Computing Center Stuttgart,
// University of Stuttgart. All rights reserved.
// Copyright (c) 2004-2005 The Regents of the University of California.
// All rights reserved.
// Copyright (c) 2006 Cisco Systems, Inc. All rights reserved.
// $COPYRIGHT$
//
// Additional copyrights may follow
//
// $HEADER$
//
class Errhandler {
public:
#if 0 /* OMPI_ENABLE_MPI_PROFILING */
// construction / destruction
inline Errhandler() { }
inline virtual ~Errhandler() { }
inline Errhandler(MPI_Errhandler i)
: pmpi_errhandler(i) { }
// copy / assignment
inline Errhandler(const Errhandler& e)
: pmpi_errhandler(e.pmpi_errhandler) { }
inline Errhandler(const PMPI::Errhandler& e)
: pmpi_errhandler(e) { }
inline Errhandler& operator=(const Errhandler& e) {
pmpi_errhandler = e.pmpi_errhandler; return *this; }
// comparison
inline bool operator==(const Errhandler &a) {
return (bool)(pmpi_errhandler == a.pmpi_errhandler); }
inline bool operator!=(const Errhandler &a) {
return (bool)!(*this == a); }
// inter-language operability
inline Errhandler& operator= (const MPI_Errhandler &i) {
pmpi_errhandler = i; return *this; }
inline operator MPI_Errhandler() const { return pmpi_errhandler; }
// inline operator MPI_Errhandler*() { return pmpi_errhandler; }
inline operator const PMPI::Errhandler&() const { return pmpi_errhandler; }
#else
// construction / destruction
inline Errhandler()
: mpi_errhandler(MPI_ERRHANDLER_NULL) {}
inline virtual ~Errhandler() { }
inline Errhandler(MPI_Errhandler i)
: mpi_errhandler(i) {}
// copy / assignment
inline Errhandler(const Errhandler& e)
: handler_fn(e.handler_fn), mpi_errhandler(e.mpi_errhandler) { }
inline Errhandler& operator=(const Errhandler& e)
{
mpi_errhandler = e.mpi_errhandler;
handler_fn = e.handler_fn;
return *this;
}
// comparison
inline bool operator==(const Errhandler &a) {
return (bool)(mpi_errhandler == a.mpi_errhandler); }
inline bool operator!=(const Errhandler &a) {
return (bool)!(*this == a); }
// inter-language operability
inline Errhandler& operator= (const MPI_Errhandler &i) {
mpi_errhandler = i; return *this; }
inline operator MPI_Errhandler() const { return mpi_errhandler; }
// inline operator MPI_Errhandler*() { return &mpi_errhandler; }
#endif
//
// Errhandler access functions
//
virtual void Free();
#if !0 /* OMPI_ENABLE_MPI_PROFILING */
Comm::Errhandler_fn* handler_fn;
#endif
protected:
#if 0 /* OMPI_ENABLE_MPI_PROFILING */
PMPI::Errhandler pmpi_errhandler;
#else
MPI_Errhandler mpi_errhandler;
#endif
public:
// took out the friend decls
//private:
//this is for ERRORS_THROW_EXCEPTIONS
//this is called from MPI::Real_init
inline void init() const {
#if ! 0 /* OMPI_ENABLE_MPI_PROFILING */
// $%%@#%# AIX/POE 2.3.0.0 makes us put in this cast here
(void)MPI_Errhandler_create((MPI_Handler_function*) &ompi_mpi_cxx_throw_excptn_fctn,
const_cast<MPI_Errhandler *>(&mpi_errhandler));
#else
pmpi_errhandler.init();
#endif
}
//this is for ERRORS_THROW_EXCEPTIONS
//this is called from MPI::Finalize
inline void free() const {
#if ! 0 /* OMPI_ENABLE_MPI_PROFILING */
(void)MPI_Errhandler_free(const_cast<MPI_Errhandler *>(&mpi_errhandler));
#else
pmpi_errhandler.free();
#endif
}
};