MPI_File_set_atomicity(3)MPI_File_set_atomicity(3)NAMEMPI_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)
DESCRIPTIONMPI_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 atomic mode semantics for outstanding requests.
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MPI_File_set_atomicity(3)MPI_File_set_atomicity(3)
Notes for Fortran
All MPI objects (for example, MPI_Datatype, MPI_Comm, MPI_File) are of
type INTEGER.
SEE ALSOMPI_File_open(3), MPI_IO(3)
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