Re: again: x11 is eating one character from stdin pipe

[Petr M. <mi...@ph...>]

> > > With the setvbuf() in place, running the awk script causes the
> > > first 120+ plot commands to be lost in transit!!!!!!
> > >
> > > Without the setvbuf() command, only a single character is
> > > dropped - the first one following the first plot command.
> >
> > I've tried it with Octave, but there is no change with or without
> > setvbuf. Gnuplot mostly looses the first character.
>
> Last night I built Octave 2.1.50 so that I could test this
> myself. What I found is that the Octave problem and the awk
> problem are not the same.
>
> The Octave problem can, I believe, be solved with the first
> patch attached below (ipc_lock.patch).  This one causes
> X11_waitforinput() to refuse to read any more characters
> using getc(stdin) while it is waiting for a response from the
> mousing pipe.
>
> This still leaves awk losing many lines of input, which is
> fixed only if I also remove the call to setvbuf() as in the
> second patch below (setvbuf.patch).
>
> Applying these two patches makes both the awk and octave
> test scripts run on my usual desktop machine under linux.
>
> I've tested both with gnu libreadline and with the builtin
> readline. But I have not yet tested on other machines, and
> I would not like to commit either patch to CVS without more
> extensive testing.
>
> In particular I am concerned that if the response from the
> mouse pipe is lost altogether, then the first patch will cause
> gnuplot will hang.  I need to add some sort of timeout or
> upper limit of attempts to read from the mouse pipe.


I'd a look to the patch of June 21 which made the break; even though I don't
understand it, I've found that commenting out the "X11_waitforinput();" call
does not produce the forgetting-pipe error:


   /* Force default font at start of plot */
#ifdef USE_MOUSE
    /* EAM June 2003 - Flush the set font command through the pipe */
    /* to gnuplot_x11, then wait for it to return the resulting    */
    /* font size information (v_char and h_char).                  */
    if (!default_font_size_known) {
        X11_set_default_font();
        FFLUSH();
        X11_waitforinput();
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        default_font_size_known = TRUE;
    }
#else
    X11_set_default_font();
#endif
    X11_set_font("");
}


Does that command have to be there?

Petr