[vdr] vdr-xine: what's wrong with this piece of code -- threading
taferner at kde.org
Fri Mar 25 10:02:30 CET 2005
On Friday 25 March 2005 09:38, Reinhard Nissl wrote:
> Stefan Taferner wrote:
> >>I'm facing a deadlock situation, when the below code is modified to
> >>ignore the "r == 0" cases (= original code in vdr-xine-0.7.2):
> > r==0 means that there is no data available. Are you sure you want
> > to block in xread until data is available?
> Yes, because there is nothing else to do at that point in time.
> > If you want to wait for data (and keep the non-blocking) you should wait
> > some time (200ms or so). If you are not sure about the cPoller, use the
> > select function with a timeout. Then you get exact error codes and all
> > that.
> All I'd like to do is to block until the requested data is ready and "r
> == 0" should just indicate that the FIFO was closed by xine.
> But for any reason, "r == 0" happens still without the FIFO beeing
> closed. Can someone tell me, how to handle this situation properly?
The read manpage says: On success, the number of bytes read is
returned (zero indicates end of file). But you probably already know that.
Here is my version of xread, taken from vdr-xine-0.7.2 with modifications.
But it is an untested version of code I wrote at work (still have no vdr at
int cXineRemote::xread(int f, void *b, int n)
int t = 0;
void (* const sigPipeHandler)(int) = ::signal(SIGPIPE, SIG_IGN);
while (t < n)
int r = ::read(f, ((char *)b) + t, n - t);
if (r < 0)
fprintf(stderr, "::read(%d) failed %d: ", n, errno);
t = -1;
else if (r == 0)
// fprintf( stderr, "::read zero bytes\n");
struct timeval tmout;
tmout.tv_sec = 3600;
tmout.tv_usec = 0;
int rc = select(f+1, &fds, 0, 0, &tmout);
fprintf(stderr, "::select returned %d\n", rc);
else t += r;
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