MPI_Startall(3OpenMPI) MPI_Startall(3OpenMPI)
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_Star-tall(count, MPI_Startall(count,
tall(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 com-pleted. completed.
pleted. It is preferable, in general, to free requests when they are inactive. If this rule is fol-lowed, followed,
lowed, 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 con-current concurrent
current 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
Open MPI 1.2 September 2006 MPI_Startall(3OpenMPI)
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