cancel.c

刚才是说明 现在是安装程序在 LINUX环境下进行编程的MPICH安装文件

/* -*- Mode: C; c-basic-offset:4 ; -*- */
/*
 *
 *  (C) 2001 by Argonne National Laboratory.
 *      See COPYRIGHT in top-level directory.
 */

#include "mpiimpl.h"

/* -- Begin Profiling Symbol Block for routine MPI_Cancel */
#if defined(HAVE_PRAGMA_WEAK)
#pragma weak MPI_Cancel = PMPI_Cancel
#elif defined(HAVE_PRAGMA_HP_SEC_DEF)
#pragma _HP_SECONDARY_DEF PMPI_Cancel  MPI_Cancel
#elif defined(HAVE_PRAGMA_CRI_DUP)
#pragma _CRI duplicate MPI_Cancel as PMPI_Cancel
#endif
/* -- End Profiling Symbol Block */

/* Define MPICH_MPI_FROM_PMPI if weak symbols are not supported to build
   the MPI routines */
#ifndef MPICH_MPI_FROM_PMPI
#define MPI_Cancel PMPI_Cancel

#endif

#undef FUNCNAME
#define FUNCNAME MPI_Cancel

/*@
    MPI_Cancel - Cancels a communication request

Input Parameter:
. request - communication request (handle) 

Note:
Cancel has only been implemented for receive requests; it is a no-op for
send requests.  The primary expected use of MPI_Cancel is in multi-buffering
schemes, where speculative MPI_Irecvs are made.  When the computation 
completes, some of these receive requests may remain; using MPI_Cancel allows
the user to cancel these unsatisfied requests.  

Cancelling a send operation is much more difficult, in large part because the 
send will usually be at least partially complete (the information on the tag,
size, and source are usually sent immediately to the destination).  As of
version 1.2.0, MPICH supports cancelling of sends.  Users are
advised that cancelling a send, while a local operation (as defined by the MPI
standard), is likely to be expensive (usually generating one or more internal
messages). 

.N fortran

.N NULL

.N Errors
.N MPI_SUCCESS
.N MPI_ERR_REQUEST
.N MPI_ERR_ARG
@*/
int MPI_Cancel(MPI_Request *request)
{
    static const char FCNAME[] = "MPI_Cancel";
    int mpi_errno = MPI_SUCCESS;
    MPID_Request * request_ptr;
    MPID_MPI_STATE_DECL(MPID_STATE_MPI_CANCEL);

#   ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
	    MPIR_ERRTEST_INITIALIZED(mpi_errno);
            if (mpi_errno) {
                return MPIR_Err_return_comm( 0, FCNAME, mpi_errno );
            }
        }
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    MPID_MPI_PT2PT_FUNC_ENTER(MPID_STATE_MPI_CANCEL);
    
    /* Convert MPI object handles to object pointers */
    MPID_Request_get_ptr( *request, request_ptr );
    
    /* Validate parameters if error checking is enabled */
#   ifdef HAVE_ERROR_CHECKING
    {
        MPID_BEGIN_ERROR_CHECKS;
        {
	    /* Validate request_ptr */
            MPID_Request_valid_ptr( request_ptr, mpi_errno );
            if (mpi_errno) {
                MPID_MPI_PT2PT_FUNC_EXIT(MPID_STATE_MPI_CANCEL);
                return MPIR_Err_return_comm( 0, FCNAME, mpi_errno );
            }
        }
        MPID_END_ERROR_CHECKS;
    }
#   endif /* HAVE_ERROR_CHECKING */

    switch (request_ptr->kind)
    {
	case MPID_REQUEST_SEND:
	{
	    MPID_Cancel_send(request_ptr);
	    break;
	}

	case MPID_REQUEST_RECV:
	{
	    MPID_Cancel_recv(request_ptr);
	    break;
	}

	case MPID_PREQUEST_SEND:
	{
	    if (request_ptr->partner_request != NULL)
	    {
		MPID_Cancel_send(request_ptr->partner_request);
	    }
	    else
	    {
		mpi_errno = MPIR_Err_create_code(MPI_ERR_REQUEST, "**requestpersistactive", 0);
	    }
	    
	    break;
	}

	case MPID_PREQUEST_RECV:
	{
	    if (request_ptr->partner_request != NULL)
	    {
		MPID_Cancel_recv(request_ptr->partner_request);
	    }
	    else
	    {
		mpi_errno = MPIR_Err_create_code(MPI_ERR_REQUEST, "**requestpersistactive", 0);
	    }

	    break;
	}

	case MPID_UREQUEST:
	{
	    mpi_errno = (request_ptr->cancel_fn)(request_ptr->grequest_extra_state, (request_ptr->cc == 0));
	    break;
	}

	default:
	{
	    mpi_errno = MPIR_Err_create_code(MPI_ERR_INTERN, "**cancelunknown", 0 );
	}
    }
    
    MPID_MPI_PT2PT_FUNC_EXIT(MPID_STATE_MPI_CANCEL);
    return (mpi_errno == MPI_SUCCESS) ? MPI_SUCCESS : MPIR_Err_return_comm(NULL, FCNAME, mpi_errno);
}