MPI_WAITALL, MPI_Waitall

Purpose

Waits for a collection of nonblocking operations to complete.

C synopsis

#include <mpi.h>
int MPI_Waitall(int count,MPI_Request *array_of_requests,
    MPI_Status *array_of_statuses);

C++ synopsis

#include mpi.h
void MPI::Request::Waitall(int count, MPI::Request req_array[]);

#include mpi.h
void MPI::Request::Waitall(int count, MPI::Request req_array[],
                           MPI::Status stat_array[]);

FORTRAN synopsis

include 'mpif.h' or use mpi
MPI_WAITALL(INTEGER COUNT,INTEGER ARRAY_OF_ REQUESTS(*),
      INTEGER ARRAY_OF_STATUSES(MPI_STATUS_SIZE,*),INTEGER IERROR)

Description

This subroutine blocks until all operations associated with active handles
in the list complete, and returns the status of each operation.
array_of_requests and array_of statuses contain count entries.

The ith entry in array_of_statuses is set to the return status of the ith
operation. Requests created by nonblocking operations are deallocated and
the corresponding handles in the array are set to MPI_REQUEST_NULL. If
array_of_requests contains null or inactive handles, MPI_WAITALL sets the
status of each one to empty.

MPI_WAITALL(count, array_of_requests, array_of_statuses) has the same
effect as the execution of MPI_WAIT(array_of_requests[i],
array_of_statuses[i]) for i = 0, 1, ..., (count-1), in some arbitrary
order. MPI_WAITALL with an array of length one is equivalent to MPI_WAIT.

The error fields are never modified unless the function gives a return code
of MPI_ERR_IN_STATUS. In which case, the error field of every MPI_Status is
modified to reflect the result of the corresponding request.

Passing MPI_STATUSES_IGNORE for the array_of statuses argument causes PE
MPI to skip filling in the status fields. By passing this value for
array_of statuses, you can avoid having to allocate a status object array
in programs that do not need to examine the status fields.

When you use this subroutine in a threads application, make sure that the
wait for a given request is done on only one thread. The wait does not have
to be done on the thread that created it. See IBM Parallel Environment for
AIX: MPI Programming Guide for more information on programming with MPI in
a threads environment.

Parameters

count
     is the lists length (integer) (IN)
array_of_requests
     is an array of requests of length count (array of handles) (INOUT)
array_of_statuses
     is an array of status objects of length count (array of status)
     (INOUT). Note that in FORTRAN a status object is itself an array.
IERROR
     is the FORTRAN return code. It is always the last argument.

Errors

A GRequest free function returned an error

A GRequest query function returned an error

Invalid status ignore value

Invalid form of status ignore

Invalid count
     count < 0

Invalid request array

Invalid request(s)

Truncation occurred

MPI not initialized

MPI already finalized

Develop mode error if:

Illegal buffer update (ISEND)

Inconsistent datatype (MPE_I collectives)

Inconsistent message length (MPE_I collectives)

Inconsistent op (MPE_I collectives)

Match of blocking and non-blocking collectives (MPE_I collectives)

Related information

     MPI_TESTALL
     MPI_WAIT