MPI_Barrier(3) Open MPI MPI_Barrier(3)
NAME
MPI_Barrier, MPI_Ibarrier - Synchronization between MPI processes in a
group
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Barrier(MPI_Comm comm)
int MPI_Ibarrier(MPI_Comm comm, MPI_Request *request)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_BARRIER(COMM, IERROR)
INTEGER COMM, IERROR
MPI_IBARRIER(COMM, REQUEST, IERROR)
INTEGER COMM, REQUEST, IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Barrier(comm, ierror)
TYPE(MPI_Comm), INTENT(IN) :: comm
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
MPI_Ibarrier(comm, request, ierror)
TYPE(MPI_Comm), INTENT(IN) :: comm
TYPE(MPI_Request), INTENT(OUT) :: request
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
#include <mpi.h>
void MPI::Comm::Barrier() const = 0
INPUT PARAMETER
comm Communicator (handle).
OUTPUT PARAMETERS
request Request (handle, non-blocking only).
IERROR Fortran only: Error status (integer).
DESCRIPTION
An MPI barrier completes after all group members have entered the bar-
rier.
WHEN COMMUNICATOR IS AN INTER-COMMUNICATOR
When the communicator is an inter-communicator, the barrier operation
is performed across all processes in both groups. All processes in the
first group may exit the barrier when all processes in the second group
have entered the barrier.
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++ func-
tions 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_Bcast
4.1.2 Nov 24, 2021 MPI_Barrier(3)
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