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MPI_Test(3)                           MPI                          MPI_Test(3)


NAME

       MPI_Test -  Tests for the completion of a request


SYNOPSIS

       int MPI_Test(MPI_Request *request, int *flag, MPI_Status *status)


INPUT PARAMETER

       request
              - MPI request (handle)


OUTPUT PARAMETER

       flag   - true if operation completed (logical)
       status - status object (Status).  May be MPI_STATUS_IGNORE .


THREAD AND INTERRUPT SAFETY

       This routine is thread-safe.  This means that this routine may be
       safely used by multiple threads without the need for any user-provided
       thread locks.  However, the routine is not interrupt safe.  Typically,
       this is due to the use of memory allocation routines such as malloc or
       other non-MPICH runtime routines that are themselves not interrupt-
       safe.

NOTES ON THE MPI_STATUS ARGUMENT
       The MPI_ERROR field of the status return is only set if the return from
       the MPI routine is MPI_ERR_IN_STATUS .  That error class is only
       returned by the routines that take an array of status arguments (
       MPI_Testall , MPI_Testsome , MPI_Waitall , and MPI_Waitsome ).  In all
       other cases, the value of the MPI_ERROR field in the status is
       unchanged.  See section 3.2.5 in the MPI-1.1 specification for the
       exact text.

       For send operations, the only use of status is for MPI_Test_cancelled
       or in the case that there is an error in one of the four routines that
       may return the error class MPI_ERR_IN_STATUS , in which case the
       MPI_ERROR field of status will be set.  In that case, the value will be
       set to MPI_SUCCESS for any send or receive operation that completed
       successfully, or MPI_ERR_PENDING for any operation which has neither
       failed nor completed.


NOTES FOR FORTRAN

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have
       an additional argument ierr at the end of the argument list.  ierr is
       an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with
       the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in
       Fortran.

       The status argument must be declared as an array of size
       MPI_STATUS_SIZE , as in integer status(MPI_STATUS_SIZE) .


ERRORS

       All MPI routines (except MPI_Wtime and MPI_Wtick ) return an error
       value; C routines as the value of the function and Fortran routines in
       the last argument.  Before the value is returned, the current MPI error
       handler is called.  By default, this error handler aborts the MPI job.
       The error handler may be changed with MPI_Comm_set_errhandler (for
       communicators), MPI_File_set_errhandler (for files), and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine
       MPI_Errhandler_set may be used but its use is deprecated.  The
       predefined error handler MPI_ERRORS_RETURN may be used to cause error
       values to be returned.  Note that MPI does not guarentee that an MPI
       program can continue past an error; however, MPI implementations will
       attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_REQUEST
              - Invalid MPI_Request .  Either null or, in the case of a
              MPI_Start or MPI_Startall , not a persistent request.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not
              identified by a specific error class (e.g., MPI_ERR_RANK ).


LOCATION

       src/mpi/pt2pt/test.c

                                   9/20/2012                       MPI_Test(3)

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