BARRIER(3PVM)							  PVM Version 3.4						     BARRIER(3PVM)

NAME

       pvm_barrier - Blocks the calling process until all processes in a group have called it.

SYNOPSIS

       C    int info = pvm_barrier( char *group, int count )

       Fortran	 call pvmfbarrier( group, count, info )

PARAMETERS

       group   Character string group name. The group must exist and the calling process must be a member of the group.

       count   Integer	specifying the number of group members that must call pvm_barrier before they are all released. Though not required, count
	       is expected to be the total number of members of the specified group.

       info    Integer status code returned by the routine.  Values less than zero indicate an error.

DESCRIPTION

       The routine pvm_barrier blocks the calling process until count members of the  group  have  called  pvm_barrier.   The  count  argument	is
       required  because  processes could be joining the given group after other processes have called pvm_barrier. Thus PVM doesn't know how many
       group members to wait for at any given instant. Although count can be set less, it is typically the total number of members of  the  group.
       So  the	logical  function  of the pvm_barrier call is to provide a group synchronization.  During any given barrier call all participating
       group members must call barrier with the same count value.  Once a given barrier has been successfully passed, pvm_barrier  can	be  called
       again by the same group using the same group name.

       If pvm_barrier is successful, info will be 0. If some error occurs then info will be < 0.

EXAMPLES

       C:
	    inum = pvm_joingroup( "worker" );
		    .
		    .
	    info = pvm_barrier( "worker", 5 );

       Fortran:
	    CALL PVMFJOINGROUP( "shakers", INUM )
	    COUNT = 10
	    CALL PVMFBARRIER( "shakers", COUNT, INFO )

ERRORS

       These error conditions can be returned by pvm_barrier

       PvmSysErr
	      pvmd was not started or has crashed.

       PvmBadParam
	      giving a count < 1.

       PvmNoGroup
	      giving a non-existent group name.

       PvmNotInGroup
	      calling process is not in specified group.

SEE ALSO

       pvm_joingroup(3PVM)

								  30 August, 1993						     BARRIER(3PVM)