io watch callback and condition modification

[Szalai Ferenc <szferi angel elte hu>]

Hello, 

I have an application using glib2.0.1 under GNU/Debian Linux. 
It creates an io watch in the default main loop context using 
g_io_add_watch_full function with an condition (G_IO_IN | G_IO_ERR |
G_IO_HUP) and callback function (do_read). 
The question is: How can I change normally the callback function (eg.:
do_write) and condition (eg.: G_IO_OUT | G_IO_ERR) without removeing and
reattaching the watch 
form the context? 

And little observation: The g_source_attach increase only the next_id
variable of context, but no one decrease it.

I hope I was clear. 

Thanks, 
Ferenc Szalai