6.27 Change between Collective and Independent Parallel Access: NF_VAR_PAR_ACCESS
The function NF_VAR_PAR_ACCESS changes whether read/write operations
on a parallel file system are performed collectively (the default) or
independently on the variable. This function can only be called if the
file was created with NF_CREATE_PAR (see NF_CREATE_PAR) or opened
with NF_OPEN_PAR (see NF_OPEN_PAR).
Calling this function affects only the open file - information about
whether a variable is to be accessed collectively or independently is
not written to the data file. Every time you open a file on a parallel
file system, all variables default to collective operations. The change
a variable to independent lasts only as long as that file is open.
The variable can be changed from collective to independent, and back,
as often as desired.
Usage
INTEGER NF_VAR_PAR_ACCESS(INTEGER NCID, INTEGER VARID, INTEGER ACCESS);
NCID- NetCDF ID, from a previous call to NF_OPEN_PAR (see NF_OPEN_PAR) or
NF_CREATE_PAR (see NF_CREATE_PAR).
varid- Variable ID.
access- NF_INDEPENDENT to set this variable to independent
operations. NF_COLLECTIVE to set it to collective operations.
Return Values
NF_NOERR- No error.
NF_ENOTVAR- No variable found.
NF_ENOTNC4- Not a netCDF-4 file.
NF_NOPAR- File not opened for parallel access.
Example
