17.2.318. MPI_Request_get_status_some

MPI_Request_get_status_some — Access information associated with an array of requests without freeing the requests.

17.2.318.1. SYNTAX

17.2.318.1.1. C Syntax

int MPI_Request_get_status_some(int incount, const MPI_Request
    array_of_requests[], int* outcount, int array_of_indices[],
    MPI_Status array_of_statuses[])

17.2.318.1.2. Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_REQUEST_GET_STATUS_SOME(INCOUNT, ARRAY_OF_REQUESTS, OUTCOUNT, ARRAY_OF_INDICES, ARRAY_OF_STATUSES, IERROR)
    INTEGER INCOUNT, ARRAY_OF_REQUESTS(*), OUTCOUNT, ARRAY_OF_INDICES(*), ARRAY_OF_STATUSES(MPI_STATUS_SIZE, *), IERROR

17.2.318.1.3. Fortran 2008 Syntax

USE mpi_f08
MPI_Request_get_status_some(incount, array_of_requests, outcount, array_of_indices, array_of_statuses, ierror)
    INTEGER, INTENT(IN) :: incount
    TYPE(MPI_Request), INTENT(IN) :: array_of_requests(incount)
    INTEGER, INTENT(OUT) :: outcount, array_of_indices(*)
    TYPE(MPI_Status) :: array_of_statuses(*)
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

17.2.318.2. INPUT PARAMETERS

  • incount: List length (non-negative integer).

  • array_of_requests: Array of requests (array of handles).

17.2.318.3. OUTPUT PARAMETERS

  • outcount: Number of completed requests (integer).

  • array_of_indices: Array of indices of operations that completed (array of integers).

  • array_of_statuses: Array of MPI_Status objects for operations that completed (array of status).

  • ierror: Fortran only: Error status (integer).

17.2.318.4. DESCRIPTION

MPI_Request_get_status_some returns in outcount the number of requests from the list array_of_requests that have completed. The first outcount locations of the array array_of_indices and array_of_statuses will contain the indices of the operations within the array array_of_requests and the status of these operations respectively. The array is indexed from zero in C and from one in Fortran. It does not deallocate or deactivate the request; a subsequent call to any of the MPI test, wait, or free routines should be executed with each completed request.

If no operation in array_of_requests is complete, it returns outcount = 0. If all operations in array_of_requests are either MPI_REQUEST_NULL or inactive, outcount will be set to MPI_UNDEFINED.

If your application does not need to examine the status field, you can save resources by using the predefined constant MPI_STATUSES_IGNORE as a special value for the array_of_statuses argument.

17.2.318.5. ERRORS

Almost all MPI routines return an error value; C routines as the return result of the function and Fortran routines in the last argument.

Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.

Open MPI includes three predefined error handlers that can be used:

  • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

  • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if MPI_Abort was called on that communicator. If called on a window or file, acts as if MPI_Abort was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.

  • MPI_ERRORS_RETURN Returns an error code to the application.

MPI applications can also implement their own error handlers by calling:

Note that MPI does not guarantee that an MPI program can continue past an error.

See the MPI man page for a full list of MPI error codes.

See the Error Handling section of the MPI-4.1 standard for more information.