MPI_File_set_atomicity - Sets the atomicity mode
SYNOPSIS
C:
#include "mpi.h"
int MPI_File_set_atomicity(MPI_File fh, int flag)
Fortran:
INCLUDE "mpif.h" (or USE MPI)
INTEGER fh, ierror
LOGICAL flag
CALL MPI_FILE_SET_ATOMICITY(fh, flag, ierror)
DESCRIPTION
MPI_File_set_atomicity sets the atomicity mode. Let fh be
the set of file handles created by one collective open
operation. This routine accepts the following arguments:
fh Specifies the file handle (handle)
flag Indicates true to set atomic mode, false to set
nonatomic mode (logical)
ierror Specifies the return code value for successful
completion, which is in MPI_SUCCESS.
MPI_SUCCESS is defined in the mpif.h file.
You can set the consistency semantics for data access
operations that use fh by collectively calling
MPI_File_set_atomicity on fh. MPI_File_set_atomicity is
collective; all processes in the group must pass identical
values for fh and flag. If flag is true, atomic mode is
set; if flag is false, nonatomic mode is set.
Changing the consistency semantics for an open file
affects only new data accesses. All completed data
accesses are guaranteed to abide by the consistency
semantics in effect during their execution. Nonblocking
data accesses and split collective operations that have
not completed (for example, because of MPI_WAIT) are
guaranteed to abide only by nonatomic mode consistency
semantics.
Because the semantics guaranteed by atomic mode are
stronger than those guaranteed by nonatomic mode, an
implementation is free to adhere to the more stringent
Notes for Fortran
All MPI objects (for example, MPI_Datatype, MPI_Comm,
MPI_File) are of type INTEGER.
SEE ALSO
MPI_File_open(3), MPI_IO(3)
Man(1) output converted with
man2html