[sane-devel] Q: threads and pipes
Hi, On Monday 12 January 2004 20:56, Oliver Rauch wrote: [SNIPSNAP] > > So I think you can't close the pipe in threads. > > > > Bye, > > Henning > > I tried what happens when the pipe is closed when threads are used. > It is better to keep the pipe opened :) indeed it is better ;-) You should always keep in mind, that when using threads you still live in the same process-space - per definition. This means, that nothing will be inheritet like in the fork case. In your reader thread you have the same pipe-descriptors, like in the main programm context. If you close it in the thread, then it's closed for the whole process. That's why I introduced the sanei_thread_is_forked() function. That's also, why the MacOSX guys want to use threads instead of fork, because of the buggy fork implementation, the descriptors are not inheritet to the child process... Good luck... Gerhard
[sane-devel] Q: threads and pipes
On Monday 12 January 2004 20:00, Henning Meier-Geinitz wrote:
> Hi,
>
> On Mon, Jan 12, 2004 at 07:42:42PM +0100, Oliver Rauch wrote:
> > Does anyone know how pipes have to be handled with threads?!
> >
> > when fork() is used then I close the read end in the reader_process a=
nd
> > the write end in the main process. Should I also do this when working
> > with threads or should I keep both ends opened ind both treads?
>
> I'm using code like this in mustek.c:
>
> if (sanei_thread_is_forked ())
> {
> DBG (4, "reader_process: using fork ()\n");
> close (s->pipe);
> s->pipe =3D -1;
> }
> else
> {
> DBG (4, "reader_process: using threads\n");
> }
>
> So I think you can't close the pipe in threads.
>
> Bye,
> Henning
I tried what happens when the pipe is closed when threads are used.
It is better to keep the pipe opened :)
Oliver
--=20
http://www.xsane.org
http://www.mostang.com/sane
http://www.rauch-domain.de
mailto:oliver.ra...@rauch-domain.de
[sane-devel] Q: threads and pipes
Hi,
On Mon, Jan 12, 2004 at 07:42:42PM +0100, Oliver Rauch wrote:
> Does anyone know how pipes have to be handled with threads?!
>
> when fork() is used then I close the read end in the reader_process and the
> write end in the main process. Should I also do this when working with
> threads or should I keep both ends opened ind both treads?
I'm using code like this in mustek.c:
if (sanei_thread_is_forked ())
{
DBG (4, "reader_process: using fork ()\n");
close (s->pipe);
s->pipe = -1;
}
else
{
DBG (4, "reader_process: using threads\n");
}
So I think you can't close the pipe in threads.
Bye,
Henning
[sane-devel] Q: threads and pipes
Hello. Does anyone know how pipes have to be handled with threads?! when fork() is used then I close the read end in the reader_process and t= he write end in the main process. Should I also do this when working with threads or should I keep both ends opened ind both treads? Oliver --=20 http://www.xsane.org http://www.mostang.com/sane http://www.rauch-domain.de mailto:oliver.ra...@rauch-domain.de
