[vdr] Re: how detect vdr has closed socket in c++?

[Sascha Volkenandt <lists@magoa.net>]

Am Dienstag, 17. Februar 2004 20:28 schrieb Guido Fiala:
> Unfortunately that does not work for writing or maybe i did try the wrong
> things...

No, you would have to check for reading before writing, actually, if you want 
to be sure the socket is open.

> -select before write and a read (i can only read 0 bytes, as i don't expect
> any byte actually there)
> -write(fd,temp,0) just before the real write - still no error

EOF isn't an error. It just means that the kernel signals "reading now 
possible", but actually returns 0 byte on reading. If the socket is open, but 
there is nothing available, select/poll don't signal the socket as 
readable...

So:
- select() on the socket for reading, timeout 0 (return immediately)
- select returns "nothing readable" -> socket open, go on with writing
- select returns "something readable" and a subsequent read returns something 
-> go on with interpreting the data :)
- select returns "something readable" but a subsequent read returns 0 -> 
socket is closed

So, you see, there's no error involved here (since all commands return ok), 
because EOF is not an error condition, but just EOF :-))


Greetings,
Sascha



-- 
Info:
To unsubscribe send a mail to ecartis@linuxtv.org with "unsubscribe vdr" as subject.