A string containing the name of a file
One of "r", "w", "a", "r+", "w+", "a+". These have the same meaning as in fopen()
Return: A #GIOChannel on success, %NULL on failure.
GException on failure. ConstructionException GTK+ fails to create the object.
Open a file @filename as a #GIOChannel using mode @mode. This channel will be closed when the last reference to it is dropped, so there is no need to call g_io_channel_close() (though doing so will not cause problems, as long as no attempt is made to access the channel after it is closed).