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

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_STARTALL(COUNT, ARRAY_OF_REQUESTS, IERROR)
            INTEGER   COUNT, ARRAY_OF_REQUESTS(*), IERROR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Startall(count, array_of_requests, ierror)
            INTEGER, INTENT(IN) :: count
            TYPE(MPI_Request), INTENT(INOUT) :: array_of_requests(count)
            INTEGER, OPTIONAL, INTENT(OUT) :: 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