H5Pget_external

herr_t H5Pget_external(hid_t plist_id,  uint  idx,  size_t name_size,
       char *  name,  off_t *  offset,  hsize_t *  size)

Gets information about an external file.

`plist_id`	Dataset creation property list identifier
`idx`	Index of the external file (0-based)
`name_size`	Size of the name buffer
`name`	Buffer to receive the external file name
`offset`	Pointer to receive the byte offset in the external file
`size`	Pointer to receive the size of the external data

Non-negative on success, negative on failure.