Adds a file descriptor to the set of file descriptors polled for
this source. This is usually combined with
g_source_new() to add an
event source. The event source’s check function will typically test
revents field in the
GPollFD struct and return
TRUE if events need
to be processed.
This API is only intended to be used by implementations of
Do not call this API on a
GSource that you did not create.
Using this API forces the linear scanning of event sources on each
main loop iteration. Newly-written event sources should try to use
g_source_add_unix_fd() instead of this API.
GPollFDstructure holding information about a file descriptor to watch.
The data is owned by the caller of the method.