Re: Concurrent Commands.

[Sven Neumann <sven gimp org>]

Hi,

CyborgHead netscape net writes:

>       I have a question regarding concurrent instructions in gtk+. I will use the following example. Consider a program that creates a window using gtk+ and also prints variables to the terminal from which the program was run. Usless program I know, but good for the example. I want to be able interact with the GUI while the numbers are being printed, but I don't know how.

> I was wondering if there was some signal function in GTK+ where a function and an interval were set. Every time of length interval a signal was sent to the program and the associated function was run. I am a native windows programmer and just new to linux, so this was my first idea.

Of course. GTK+ is all about signals and callbacks. The following code
should work:

[construct GUI here]

gtk_timeout_add (1000, print_number, NULL);

gtk_main ();


and would call function print_number() every second.

> I have also done some reading on a function fork(), which created two threads through the program. In theory I think that this might work, but am not sure. Does anyone know?

Using multiple processes is sometimes necessary, but can be avoided for
most apps.

I think you should start by reading the GTK+ tutorial on www.gtk.org. It 
explains signals and callbacks in the first chapters and goes into more 
detail (idle functions, timeouts) somewhere around chapter 18.


Salut, Sven