GLIO_GROUP(3F) Last changed: 2-24-98
NAME
glio_group_mpi, glio_group_shmem - Defines a group of processes to be
associated with a global file.
SYNOPSIS
C or C++:
#include <ffio.h>
#include <mpi.h>
void glio_group_mpi(MPI_Comm comm)
#include <mpp/shmem.h>
void glio_group_shmem(int handle);
Fortran:
include "mpif.h"
INTEGER comm
CALL GLIO_GROUP_MPI(comm)
include "mpp/shmem.fh"
INTEGER handle
CALL GLIO_GROUP_SHMEM(handle);
IMPLEMENTATION
UNICOS/mk and IRIX systems
DESCRIPTION
These subroutines identify the group of processes which will share
access to any FFIO files opened with the global FFIO layer. These
files, termed global files, must be opened and closed collectively by
all processes that share access to them.
The following is a list of valid arguments for these routines:
comm An MPI communicator. The group of processes associated with
this communicator will access the global file. This process
group must be executing within a single host machine.
handle A SHMEM process group handle returned from the
shmem_group_create_strided() function.
The glio_group_mpi and glio_group_shmem functions are collective
across the set of processes identified by comm or handle.
If glio_group_mpi or glio_group_shmem are not called prior to an open
of a global file, all MPI or SHMEM processes in the application must
collectively open and close the file.
EXAMPLES
The following Fortran program opens global file globfile for access
from SHMEM processes (PEs) 0 and 1. PEs 2 and higher will not access
the file.
program global_subset
include "mpp/shmem.fh"
integer racom, handle
common /racom/ racom(SHMEM_GROUP_COM_SIZE)
call start_pes(0)
racom = 0
c Define a SHMEM group and then open globfile across this group
if (my_pe().le.1) then
call assign("assign -F global u:20",ier)
handle = shmem_group_create_strided(0, 1, 2, racom, shmem_null)
call glio_group_shmem(handle)
open (20,file="globfile",access="direct",recl=64)
endif
end
SEE ALSOshmem_group_create_strided(3)
Application Programmer's Library Reference Manual, publication
SR-2165, for the printed version of this man page.
