MPI_Startall(3)                    Open MPI                    MPI_Startall(3)



NAME
       MPI_Startall - Starts a collection of requests.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Startall(int count, MPI_Request *array_of_requests)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_STARTALL(COUNT, ARRAY_OF_REQUESTS, IERROR)
            INTEGER   COUNT, ARRAY_OF_REQUESTS(*), IERROR


C++ Syntax
       #include <mpi.h>
       static void Prequest::Startall(int count, Prequest array_of_requests[])


INPUT PARAMETER
       count     List length (integer).


INPUT/OUTPUT PARAMETER
       array_of_requests
                 Array of requests (array of handle).


OUTPUT PARAMETER
       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       Starts all communications associated with requests in
       array_of_requests. A call to  MPI_Startall(count, array_of_requests)
       has the same effect as calls to MPI_Start (&array_of_requests[i]),
       executed for i=0 ,..., count-1, in some arbitrary order.

       A communication started with a call to MPI_Start or MPI_Startall is
       completed by a call to MPI_Wait, MPI_Test, or one of the derived
       functions MPI_Waitany, MPI_Testany, MPI_Waitall, MPI_Testall,
       MPI_Waitsome, MPI_Testsome (these are described in Section 3.7.5 of the
       MPI-1 Standard, "Multiple Completions"). The request becomes inactive
       after successful completion by such a call. The request is not
       deallocated, and it can be activated anew by another MPI_Start or
       MPI_Startall call.

       A persistent request is deallocated by a call to MPI_Request_free (see
       Section 3.7.3  of the MPI-1 Standard, "Communication Completion").

       The call to MPI_Request_free can occur at any point in the program
       after the persistent request was created. However, the request will be
       deallocated only after it becomes inactive. Active receive requests
       should not be freed. Otherwise, it will not be possible to check that
       the receive has completed. It is preferable, in general, to free
       requests when they are inactive. If this rule is followed, then the
       persistent communication request functions will be invoked in a
       sequence of the form,

           Create (Start Complete)* Free

       where * indicates zero or more repetitions. If the same communication
       object is used in several concurrent threads, it is the user's
       responsibility to coordinate calls so that the correct sequence is
       obeyed.

       A send operation initiated with MPI_Start can be matched with any
       receive operation and, likewise, a receive operation initiated with
       MPI_Start can receive messages generated by any send operation.


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; 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.


SEE ALSO
       MPI_Bsend_init
       MPI_Rsend_init
       MPI_Send_init
       MPI_Ssend_init
       MPI_Recv_init
       MPI_Start
       MPI_Request_free





1.4.1                            Jan 14, 2010                  MPI_Startall(3)
