|MPI_BARRIER( comm )|
|IN comm||communicator (handle)|
int MPI_Barrier(MPI_Comm comm )
INTEGER COMM, IERROR
void MPI::Comm::Barrier() const = 0
If comm is an intracommunicator, MPI_BARRIER blocks the caller until all group members have called it. The call returns at any process only after all group members have entered the call. If comm is an intercommunicator, the barrier is performed across all processes in the intercommunicator. In this case, all processes in one group (group A) of the intercommunicator may exit the barrier when all of the processes in the other group (group B) have entered the barrier.