MPI_Waitall(3OpenMPI) MPI_Waitall(3OpenMPI)
NAME
MPI_Waitall - Waits for all given communications to complete.
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Waitall(int count, MPI_Request *array_of_requests,
MPI_Status *array_of_statuses)
Fortran Syntax
INCLUDE 'mpif.h'
MPI_WAITALL(COUNT, ARRAY_OF_REQUESTS, ARRAY_OF_STATUSES, IERROR)
INTEGER COUNT, ARRAY_OF_REQUESTS(*)
INTEGER ARRAY_OF_STATUSES(MPI_STATUS_SIZE,*), IERROR
C++ Syntax
#include <mpi.h>
static void Request::Waitall(int count, Request array_of_requests[],
Status array_of_statuses[])
static void Request::Waitall(int count, Request array_of_requests[])
INPUT PARAMETERS
count Lists length (integer).
array_of_requests
Array of requests (array of handles).
OUTPUT PARAMETERS
array_of_statuses
Array of status objects (array of status).
IERROR Fortran only: Error status (integer).
DESCRIPTION
Blocks until all communication operations associated with active handles in the list complete, and
returns the status of all these operations (this includes the case where no handle in the list is
active). Both arrays have the same number of valid entries. The ith entry in array_of_statuses is set
to the return status of the ith operation. Requests that were created by nonblocking communication
operations are deallocated, and the corresponding handles in the array are set to MPI_REQUEST_NULL.
The list may contain null or inactive handles. The call sets to empty the status of each such entry.
The error-free execution of MPI_Waitall(count, array_of_requests, array_of_statuses) has the same
effect as the execution of MPI_Wait(&array_of_request[i], &array_of_statuses[i]), for
i=0,...,count-1, in some arbitrary order. MPI_Waitall with an array of length 1 is equivalent to
MPI_Wait.
When one or more of the communications completed by a call to MPI_Waitall fail, it is desirable to
return specific information on each communication. The function MPI_Waitall will return in such case
the error code MPI_ERR_IN_STATUS and will set the error field of each status to a specific error
code. This code will be MPI_SUCCESS if the specific communication completed; it will be another spe-cific specific
cific error code if it failed; or it can be MPI_ERR_PENDING if it has neither failed nor completed.
The function MPI_Waitall will return MPI_SUCCESS if no request had an error, or will return another
error code if it failed for other reasons (such as invalid arguments). In such cases, it will not
update the error fields of the statuses.
If your application does not need to examine the array_of_statuses field, you can save resources by
using the predefined constant MPI_STATUSES_IGNORE can be used as a special value for the
array_of_statuses argument.
ERRORS
For each invocation of MPI_Waitall, if one or more requests generate an MPI exception, only the first
MPI request that caused an exception will be passed to its corresponding error handler. No other
error handlers will be invoked (even if multiple requests generated exceptions). However, all
requests that generate an exception will have a relevant error code set in the corresponding sta-tus.MPI_ERROR status.MPI_ERROR
tus.MPI_ERROR field (unless MPI_IGNORE_STATUSES was used).
The default error handler aborts the MPI job, except for I/O function errors. The error handler may
be changed with MPI_Comm_set_errhandler, MPI_File_set_errhandler, or MPI_Win_set_errhandler (depend-ing (depending
ing on the type of MPI handle that generated the MPI request); 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.
If the invoked error handler allows MPI_Waitall to return to the caller, the value MPI_ERR_IN_STATUS
will be returned in the C and Fortran bindings. In C++, if the predefined error handler
MPI::ERRORS_THROW_EXCEPTIONS is used, the value MPI::ERR_IN_STATUS will be contained in the
MPI::Exception object. The MPI_ERROR field can then be examined in the array of returned statuses to
determine exactly which request(s) generated an exception.
SEE ALSO
MPI_Comm_set_errhandler
MPI_File_set_errhandler
MPI_Test
MPI_Testall
MPI_Testany
MPI_Testsome
MPI_Wait
MPI_Waitany
MPI_Waitsome
MPI_Win_set_errhandler
Open MPI 1.2 September 2006 MPI_Waitall(3OpenMPI)
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