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 opera-
tions (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 com-
munication. 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 specific 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_STA-
TUSES_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 excep-
tions). However, all requests that generate an exception will have a relevant error code set in the corresponding status.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_errhan-
dler, MPI_File_set_errhandler, or MPI_Win_set_errhandler (depending on the type of MPI handle that generated the MPI request); the prede-
fined error handler MPI_ERRORS_RETURN may be used to cause error values to be returned. Note that MPI does not guarantee that an MPI pro-
gram 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)