[MPlayer-dev-eng] mplayer slave mode question

[Rich Felker]

On Mon, Aug 27, 2007 at 05:45:17PM -0500, Kevron Rees wrote:
> From my experience, I can successfully pipe commands to mplayer through
> mplayer's stdin.  I can also create a pipe from mplayer's stdout but
> whenever I retrieve info from mplayer via that fd, I get blocking and my
> program locks up.  I haven't found any code that has two way
> communication with mplayer.  Most frontends just seem to issue system()
> commands or a single popen("mplayer", "w") pipe.
> 
> To work around this problem, I want to be able to pipe mplayer's stdout
> to a file in which I can just purge anytime I want new data.  However, I
> don't know how I can do this.  Mplayer doesn't have a -stdout=foo.txt
> does it?

The question is about your programming language, not MPlayer, but the
short answer is that you need to dump popen() (which creates nasty
FILE* that can't really be used for anything interactive) and use the
pipe() syscall directly, along with fork(), exec*(), and some sort of
non-blocking read (either set the file descriptors from pipe() to
nonblocking mode in the parent process, or use select() to decide when
to read).

Hope this helps!

Rich