I do not know where you found get_file_size and get_file_extent.
section 10.5.1 Canonical Data Size and Extent; page 216 in the Oct 19th
version of the document.
In order to be more consistent, I would recommend to use for all
get/set functions related to I/O the format:
get_file_xxx and set_file_xxx
Therefore, we would get the following set:
get_file_amode
get_file_atomicity
set_file_atomicity
get_file_comm
get_file_info
set_file_info
get_file_position
get_file_position_shared
get_file_size
get_file_view
set_file_view
These names look good to me.