MPI_Waitall(3) Open MPI MPI_Waitall(3)
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
USE MPI
! or the older form: 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
Fortran 2008 Syntax
USE mpi_f08
MPI_Waitall(count, array_of_requests, array_of_statuses, ierror)
INTEGER, INTENT(IN) :: count
TYPE(MPI_Request), INTENT(INOUT) :: array_of_requests(count)
TYPE(MPI_Status) :: array_of_statuses(*)
INTEGER, OPTIONAL, INTENT(OUT) :: 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 han-
dles 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 ar-
ray_of_statuses is set to the return status of the ith operation. Re-
quests 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, ar-
ray_of_statuses) has the same effect as the execution of MPI_Wait(&ar-
ray_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_Wait-
all fail, it is desirable to return specific information on each commu-
nication. 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 com-
munication completed; it will be another specific error code if it
failed; or it can be MPI_ERR_PENDING if it has neither failed nor com-
pleted. 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 exceptions). How-
ever, all requests that generate an exception will have a relevant er-
ror code set in the corresponding status.MPI_ERROR field (unless
MPI_STATUSES_IGNORE 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 (depending on the
type of MPI handle that generated the MPI request); the predefined er-
ror 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 con-
tinue 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 For-
tran bindings. In C++, if the predefined error handler MPI::ER-
RORS_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
4.1.2 Nov 24, 2021 MPI_Waitall(3)
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