Open an existing file.

Parameters

[in] iosys The handle to the I/O system. IO system descriptor structure.

This structure contains the general IO subsystem data and MPI structure

Parameters

[out] file The handle to the opened file is returned via this arg.

File descriptor structure.

This structure holds information associated with each open file

Parameters

[in,out] iotype The I/O type to use to open the file. The library can modify the I/O type when retrying with other I/O types (when the user specified I/O type fails). If a different I/O type is used by the library this argument is updated accordingly. An integer parameter that controls the underlying I/O library and the I/O library-specific options (compression etc) used by the library.

Note that since an iotype is associated with a file, two different files can potentially be associated with two different iotypes.

PIO_iotype_pnetcdf : parallel read/write using the PnetCDF library
PIO_iotype_netcdf : serial (only the root I/O process) read/write using the NetCDF library
PIO_iotype_netcdf4c : parallel read/serial write of NetCDF4 (HDF5) files with data compression
PIO_iotype_netcdf4p : parallel read/write of NETCDF4 (HDF5) files
PIO_iotype_netcdf4p_nczarr : parallel read/write of NETCDF4 NCZarr files
PIO_iotype_adios : parallel read/write of ADIOS files
PIO_iotype_adiosc : parallel read/write of ADIOS files with data compression

PIO_iotype_hdf5 : parallel write of HDF5 files

Parameters

[in]	fname	The name of the file to be opened
[in]	mode	(Optional) The file access mode. : The flags to specify the file access mode when opening a file PIO_WRITE : Using this flag an existing file is opened in "write" mode PIO_NOWRITE : Using this flag an existing file is opened in "read-only" mode

Returns: : The error return code.

Set to PIO_NOERR on success, or an error code otherwise (See PIO_seterrorhandling for more information on how to customize/set error handling)