MPI_File_set_atomicity(3OpenMPI) MPI_File_set_atomicity(3OpenMPI)
NAME
MPI_File_set_atomicity - Sets consistency semantics for data-access operations (collective).
SYNTAX
C Syntax
#include <mpi.h>
int MPI_File_set_atomicity(MPI_File fh, int flag)
Fortran Syntax
INCLUDE 'mpif.h'
MPI_FILE_SET_ATOMICITY(FH, FLAG, IERROR)
INTEGER FH, FLAG, IERROR
C++ Syntax
#include <mpi.h>
void MPI::File::Set_atomicity(bool flag)
INPUT PARAMETERS
fh File handle (handle).
flag true to enable atomic mode, false to enable nonatomic mode (boolean).
OUTPUT PARAMETER
IERROR Fortran only: Error status (integer).
DESCRIPTION
The consistency semantics for data-access operations using the set of file handles created by one collective MPI_File_open is set by col-
lectively calling MPI_File_set_atomicity. 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.
The default value on a call to MPI_File_open in Open MPI is true for jobs running on more than one node, false for jobs running on a single
SMP. For more information, see the MPI-2 standard.
ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
tions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
will be used to throw an MPI:Exception object.
Before the error value is returned, the current MPI error handler is called. For MPI I/O function errors, the default error handler is set
to MPI_ERRORS_RETURN. The error handler may be changed with MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may
be used to make I/O errors fatal. Note that MPI does not guarantee that an MPI program can continue past an error.
Open MPI 1.2 September 2006 MPI_File_set_atomicity(3OpenMPI)