NAME¶
MPI_Testany - Tests for completion of any one previously initiated
communication 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¶
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
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)
- 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 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.
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.
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.
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