glib:key-file-load-from-data-dirs (keyfile file flags)

keyfile -- a g:key-file instance
file -- a string for the relative path to a filename to open and parse
flags -- a g:key-file-flags value

The string containing the full path of the file, or nil if the file could not be loaded.

This function looks for a key file named file in the paths returned from the g_get_user_data_dir() and g_get_system_data_dirs() functions, loads the file into keyfile and returns the full path of the file. If the file could not be loaded then nil is returned.