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MPI_Testany - Tests for completion of any one previously initiated
communication in a list.
#include <mpi.h>
int MPI_Testany(int count, MPI_Request array_of_requests[],
int *index, int *flag, MPI_Status *status)
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
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
- count
- List length (integer).
- array_of_requests
- Array of
requests (array of handles).
- 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).
MPI_Testany tests
for completion of either one or none of the operations 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 deallocated and the handle is set to MPI_REQUEST_NULL.
(The array is indexed from 0 in C, and from 1 in Fortran.) In the latter
case (no operation completed), it returns flag = false, returns a value
of MPI_UNDEFINED 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 effect 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.
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.
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_errhandler (depending on the type of MPI handle that generated
the request); 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 status. 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 handler MPI_ERRORS_RETURN exhibits this behavior, for example.
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
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