MPI_Testany(3)                     Open MPI                     MPI_Testany(3)



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)


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
       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




1.4.1                            Jan 14, 2010                   MPI_Testany(3)
