NAME¶
MPI_Barrier, MPI_Ibarrier - Synchronization between MPI processes in a
group
C Syntax¶
#include <mpi.h>
int MPI_Barrier(MPI_Comm comm)
int MPI_Ibarrier(MPI_Comm comm, MPI_Request *request)
Fortran Syntax¶
INCLUDE 'mpif.h'
MPI_BARRIER(COMM, IERROR)
INTEGER COMM, IERROR
MPI_IBARRIER(COMM, REQUEST, IERROR)
INTEGER COMM, REQUEST, IERROR
C++ Syntax¶
#include <mpi.h>
void MPI::Comm::Barrier() const = 0
- 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 barrier.
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++ functions 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.
