17.2.26. MPI_Barrier_init

MPI_Barrier, MPI_Ibarrier - Synchronization between MPI processes in a group

17.2.26.1. Syntax

17.2.26.1.1. C Syntax

#include <mpi.h>

int MPI_Barrier(MPI_Comm)
int MPI_Ibarrier(MPI_Comm comm, MPI_Request *request)
int MPI_barrier_init(MPI_Comm comm, MPI_Info info, MPI_Request *request)

17.2.26.1.2. 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
MPI_BARRIER_INIT(COMM, INFO, REQUEST, IERROR)
    INTEGER COMM, INFO, REQUEST, IERROR

17.2.26.1.3. 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
MPI_Barrier_init(comm, info, request, ierror)
    TYPE(MPI_Comm), INTENT(IN) :: comm
    TYPE(MPI_Info), INTENT(IN) :: info
    TYPE(MPI_Request), INTENT (OUT) :: request
    INTEGER, OPTIONAL, INTENT(OUT) :: ierror

17.2.26.2. Input Parameter

  • comm : Communicator (handle).

  • info : Info (handle, persistent only).

17.2.26.3. Output Parameters

  • request : Request (handle, non-blocking only).

  • IERROR : Fortran only: Error status (integer).

17.2.26.4. Description

An MPI barrier completes after all groups members have entered the barrier.

17.2.26.5. 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.

17.2.26.6. Errors

Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. 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