fd for the IO events in
The tag returned by this function can be used to remove or modify the
monitoring of the fd using
g_source_remove_unix_fd() or g_source_modify_unix_fd().
It is not necessary to remove the fd before destroying the source; it will be cleaned up automatically.
This API is only intended to be used by implementations of
Do not call this API on a
GSource that you did not create.
As the name suggests, this function is not available on Windows.
Available since: 2.36
The fd to monitor.
An event mask.