17.2.140. MPI_File_set_atomicity
MPI_File_set_atomicity - Sets consistency semantics for data-access operations (collective).
17.2.140.1. SYNTAX
17.2.140.1.1. C Syntax
#include <mpi.h>
int MPI_File_set_atomicity(MPI_File fh, int flag)
17.2.140.1.2. Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_FILE_SET_ATOMICITY(FH, FLAG, IERROR)
INTEGER FH, FLAG, IERROR
17.2.140.1.3. Fortran 2008 Syntax
USE mpi_f08
MPI_File_set_atomicity(fh, flag, ierror)
TYPE(MPI_File), INTENT(IN) :: fh
LOGICAL, INTENT(IN) :: flag
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
17.2.140.2. INPUT PARAMETERS
fh
: File handle (handle).flag
: true to enable atomic mode, false to enable nonatomic mode (boolean).
17.2.140.3. OUTPUT PARAMETER
IERROR
: Fortran only: Error status (integer).
17.2.140.4. DESCRIPTION
The consistency semantics for data-access operations using the set of file handles created by one collective MPI_File_open is set by collectively 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.
17.2.140.5. ERRORS
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
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.