Re: wxt term + osx

[Allin C. <cot...@wf...>]

On Tue, 25 Aug 2015, Allin Cottrell wrote:

> On Tue, 25 Aug 2015, Jun T. wrote:
>
>> 2015/08/25 12:43, Allin Cottrell <cot...@wf...> wrote:
>> 
>>> But if I do the same thing programmatically (using the GLib function
>>> g_spawn_async) the wxt window appears momentarily, with the plot
>>> looking OK so far as I can tell, then disappears right away. The
>>> GLib call seems to be correct; it works as intended on Linux.
>>> Somehow on OS X the "pause mouse close" isn't preventing the
>>> termination of the gnuplot process.
>> 
>> I have no experience with glib, but I guess the stdin of the
>> spawned gnuplot is set to /dev/null, so the gnuplot thinks it
>> should quit (as if you typed ctrl-D in the terminal = EOF).
>> 
>> On Linux, wxt window is managed by a separate process from the main
>> gnuplot process. But on Mac, gnuplot+wxt is a single process, and if
>> the main gnuplot quits then the plot window will go away.
>> 
>> You may try setting the G_SPAWN_CHILD_INHERITS_STDIN bit in the
>> 'flags' (the 4th arg of g_spawn_async()), so that the gnuplot will
>> inherit the stdin from the parent.
>
> Thanks, your diagnosis seems to be accurate. Unfortunately the program from 
> which I'm calling gnuplot is a GUI program so it doesn't have a STDIN that 
> gnuplot can inherit.
>
> I have found one way to get gnuplot/wxt to stay open in this context bit it's 
> seriously clunky: write out a shell script that calls gnuplot with the 
> plot-script argument, then use system() to call Terminal.app to execute the 
> shell script. The Terminal.app window is just in the way and doesn't close 
> itself on exit.
>
> One thing I'm still not getting: you're right that g_spawn sets the child's 
> stdin to /dev/null by default, but then I wonder how gnuplot stays open on 
> Linux? As I understand it, gnuplot itself must still be running if the 3D 
> plot can be manipulated with the mouse.

Thinking some more about what you said, I think I'm closer to a 
workable solution: use g_spawn_async_with_pipes, which enables you to 
grab a file descriptor for the child's (i.e. gnuplot's) stdin; then 
pipe the script through that instead of supplying its name as a 
command-line argument. But now the problem is that gnuplot doesn't 
quit when the wxt window is closed, it continues running in the 
background. Urgh!

Allin Cottrell