MPI_Testany(3) Open MPI MPI_Testany(3)
NAME
MPI_Testany - Tests for completion of any one previously initiated com-
munication in a list.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Testany(int count, MPI_Request array_of_requests[],
int *index, int *flag, MPI_Status *status)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_TESTANY(COUNT, ARRAY_OF_REQUESTS, INDEX, FLAG, STATUS, IERROR)
LOGICAL FLAG
INTEGER COUNT, ARRAY_OF_REQUESTS(*), INDEX
INTEGER STATUS(MPI_STATUS_SIZE), IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Testany(count, array_of_requests, index, flag, status, ierror)
INTEGER, INTENT(IN) :: count
TYPE(MPI_Request), INTENT(INOUT) :: array_of_requests(count)
INTEGER, INTENT(OUT) :: index
LOGICAL, INTENT(OUT) :: flag
TYPE(MPI_Status) :: status
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
static bool Request::Testany(int count, Request array_of_requests[],
int& index, Status& status)
static bool Request::Testany(int count, Request array_of_requests[],
int& index)
INPUT PARAMETERS
count List length (integer).
array_of_requests
Array of requests (array of handles).
OUTPUT PARAMETERS
index Index of operation that completed, or MPI_UNDEFINED if none
completed (integer).
flag True if one of the operations is complete (logical).
status Status object (status).
IERROR Fortran only: Error status (integer).
DESCRIPTION
MPI_Testany tests for completion of either one or none of the opera-
tions associated with active handles. In the former case, it returns
flag = true, returns in index the index of this request in the array,
and returns in status the status of that operation; if the request was
allocated by a nonblocking communication call then the request is de-
allocated and the handle is set to MPI_REQUEST_NULL. (The array is in-
dexed from 0 in C, and from 1 in Fortran.) In the latter case (no oper-
ation completed), it returns flag = false, returns a value of MPI_UNDE-
FINED in index, and status is undefined.
The array may contain null or inactive handles. If the array contains
no active handles then the call returns immediately with flag = true,
index = MPI_UNDEFINED, and an empty status.
If the array of requests contains active handles then the execution of
MPI_Testany(count, array_of_requests, index, status) has the same ef-
fect as the execution of MPI_Test(&array_of_requests[i], flag, status),
for i=0,1,...,count-1, in some arbitrary order, until one call returns
flag = true, or all fail. In the former case, index is set to the last
value of i, and in the latter case, it is set to MPI_UNDEFINED.
MPI_Testany with an array containing one active entry is equivalent to
MPI_Test.
If your application does not need to examine the status field, you can
save resources by using the predefined constant MPI_STATUS_IGNORE as a
special value for the status argument.
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++ func-
tions 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.
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, MPI_File_set_errhandler, or MPI_Win_set_er-
rhandler (depending on the type of MPI handle that generated the re-
quest); 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.
Note that per MPI-1 section 3.2.5, MPI exceptions on requests passed to
MPI_TESTANY do not set the status.MPI_ERROR field in the returned sta-
tus. The error code is passed to the back-end error handler and may be
passed back to the caller through the return value of MPI_TESTANY if
the back-end error handler returns it. The pre-defined MPI error han-
dler MPI_ERRORS_RETURN exhibits this behavior, for example.
SEE ALSO
MPI_Comm_set_errhandler
MPI_File_set_errhandler
MPI_Test
MPI_Testall
MPI_Testsome
MPI_Wait
MPI_Waitall
MPI_Waitany
MPI_Waitsome
MPI_Win_set_errhandler
4.1.2 Nov 24, 2021 MPI_Testany(3)
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