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)
- 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 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.
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++ functions 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.