75 строки
3.2 KiB
Groff
75 строки
3.2 KiB
Groff
|
.\"Copyright 2006, Sun Microsystems, Inc. All rights reserved. Use is subject to license terms.
|
||
|
|
.\" Copyright (c) 1996 Thinking Machines Corporation
|
||
|
|
.TH MPI_Test 3OpenMPI "September 2006" "Open MPI 1.2" " "
|
||
|
|
.SH NAME
|
||
|
|
\fBMPI_Test\fP \- Tests for the completion of a specific send or receive.
|
||
|
|
|
||
|
|
.SH SYNTAX
|
||
|
|
.ft R
|
||
|
|
.SH C Syntax
|
||
|
|
.nf
|
||
|
|
#include <mpi.h>
|
||
|
|
int MPI_Test(MPI_Request *\fIrequest\fP, int\fI *flag\fP, MPI_Status\fI *status\fP)
|
||
|
|
|
||
|
|
.SH Fortran Syntax
|
||
|
|
.nf
|
||
|
|
INCLUDE 'mpif.h'
|
||
|
|
MPI_TEST(\fIREQUEST, FLAG, STATUS, IERROR\fP)
|
||
|
|
LOGICAL \fIFLAG\fP
|
||
|
|
INTEGER \fIREQUEST, STATUS(MPI_STATUS_SIZE), IERROR\fP
|
||
|
|
|
||
|
|
.SH C++ Syntax
|
||
|
|
.nf
|
||
|
|
#include <mpi.h>
|
||
|
|
bool Request::Test(Status& \fIstatus\fP)
|
||
|
|
|
||
|
|
bool Request::Test()
|
||
|
|
|
||
|
|
.SH INPUT PARAMETER
|
||
|
|
.ft R
|
||
|
|
.TP 1i
|
||
|
|
request
|
||
|
|
Communication request (handle).
|
||
|
|
|
||
|
|
.SH OUTPUT PARAMETERS
|
||
|
|
.ft R
|
||
|
|
.TP 1i
|
||
|
|
flag
|
||
|
|
True if operation completed (logical).
|
||
|
|
.TP 1i
|
||
|
|
status
|
||
|
|
Status object (status).
|
||
|
|
.ft R
|
||
|
|
.TP 1i
|
||
|
|
IERROR
|
||
|
|
Fortran only: Error status (integer).
|
||
|
|
|
||
|
|
.SH DESCRIPTION
|
||
|
|
.ft R
|
||
|
|
A call to MPI_Test returns flag = true if the operation identified by request is complete. In such a case, the status object is set to contain information on the completed operation; if the communication object was created by a nonblocking send or receive, then it is deallocated and the request handle is set to MPI_REQUEST_NULL. The call returns flag = false, otherwise. In this case, the value of the status object is undefined. MPI_Test is a local operation.
|
||
|
|
.sp
|
||
|
|
The return status object for a receive operation carries information that can be accessed as described in Section 3.2.5 of the MPI-1 Standard, "Return Status." The status object for a send operation carries information that can be accessed by a call to MPI_Test_cancelled (see Section 3.8 of the MPI-1 Standard, "Probe and Cancel").
|
||
|
|
.sp
|
||
|
|
If your application does not need to examine the \fIstatus\fP field, you can save resources by using the predefined constant MPI_STATUS_IGNORE as a special value for the \fIstatus\fP argument.
|
||
|
|
.sp
|
||
|
|
One is allowed to call MPI_Test with a null or inactive \fIrequest\fP argument. In such a case the operation returns with \fIflag\fP = true and empty \fIstatus\fP.
|
||
|
|
.sp
|
||
|
|
The functions MPI_Wait and MPI_Test can be used to complete both sends and
|
||
|
|
receives.
|
||
|
|
|
||
|
|
.SH NOTES
|
||
|
|
The use of the nonblocking MPI_Test call allows the user to schedule alternative activities within a single thread of execution. An event-driven thread scheduler can be emulated with periodic calls to MPI_Test.
|
||
|
|
|
||
|
|
.SH ERRORS
|
||
|
|
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ functions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw an MPI:Exception object.
|
||
|
|
.sp
|
||
|
|
Before the error value is returned, the current MPI error handler is
|
||
|
|
called. By default, this error handler aborts the MPI job, except for I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.
|
||
|
|
|
||
|
|
.SH SEE ALSO
|
||
|
|
.ft R
|
||
|
|
.sp
|
||
|
|
MPI_Wait
|
||
|
|
|
||
|
|
' @(#)MPI_Test.3 1.20 06/03/09
|