H5P_SET_FAPL_MPIPOSIX stores the user-supplied MPI IO parameter comm , for communicator, in the file access property list fapl_id . That property list can then be used to create and/or open the file. H5P_SET_FAPL_MPIPOSIX is available only in the parallel HDF5 library and is not a collective function. comm is the MPI communicator to be used for file open, as defined in MPI_FILE_OPEN of MPI-2. This function does not create a duplicated communicator. Modifications to comm after this function call returns may have an undetermined effect on the file access property list. Users should not modify the communicator while it is defined in a property list.
use_gpfs_hints specifies whether to attempt to use GPFS hints when accessing this file. A value of TRUE (or 1 ) indicates that the hints should be used, if possible. A value of FALSE (or 0 ) indicates that the hints should not be used.
Available GPFS hints are known to the HFD5 library and are not user configurable. They may be used only with GPFS file systems and may improve file access for some applications; the user of a GPFS system is encouraged to experiment by running an application with and without this parameter set. |