Windows ginput function [Was: fopen doesn't return when opening a fifo!!]

[David Bateman]

John W. Eaton wrote:
> | Additionally what if the user is a fast clicker, and is faster than the
> | arbitrary 0.1s delay. This will result in missed clicks.. I therefore
> | thinks its better to not sleep, or use blocking reads.
>
> I don't understand why there would be missed clicks, but maybe I'm
> missing something about the implementation in gnuplot.  Wouldn't the
> information about the clicks be written to the output regardless of
> what Octave is doing?  Oh, I see now, we are only catching one click
> for each "pause mouse any" command.  Never mind.
>   
The reason is that the ginput command issues a "pause mouse any" to
gnuplot and then accepts the next click. If Octave doesn't issue the
next "pause mouse any" before the user clicks then the click will be lost.

> | I believe the attached patch should work as you'd like it to.
>
> OK, I applied it.
>
> Instead of checking ispc(), maybe we should just try mkfifo and see
> whether it works and if not, use in-line communication?  Check the
> definition of file_ops::mkfifo in liboctave/file-ops.cc.  If the
> mkfifo system call is not available, mkfifo should return err == -1
> and msg == "mkfifo: not supported on this system".
>   
Cygwin has a mkfifo function. However its a stub, so the test for the
existence of mkfifo on cygwin will succeed, but it wont later work as
expected. This is why I tested on ispc() rather than for HAVE_MKFIFO in
the config.

D.


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