[maemo-developers] [maemo-developers] using execl

[From: Tomas Junnonen]

ext Brad Burleson wrote:
> I'm probably doing something stupid, but I'm trying to write a home 
> plug-in that executes a shell script (which, in turn, will eventually 
> launch some application).  I hacked the code from one of the nokia 
> 'hello-world-app' programs and except for struggling with the gnu build 
> tools (and my own ignorance) things are going well.
>  
> My code looks like this:
>  
>   execl("/bin/sh", "sh", "-c", "pplay", (char *)0);
>  
> When I do this within a callback, as soon as the button is clicked the 
> screen turns white and the script - and application - runs, but the UI 
> is broken - hard to explain, but it's not drawn completely and the only 
> function that seems to work is to close the program.  At which point, 
> the 770 reboots.
>  
> (my feeble mind says it must be related to the [l]eave part of execl())
>  
> Any tips on how to execute a shell script (or any binary) from a maemo 
> application?

The home plugins do not have their own main loop but use the desktop's, 
so when you call execl the desktop process image is in fact replaced 
with that of the called program.

As pete said, you should use the g_spawn_* functions instead. In 
practice you should only ever be using the async versions in the home 
plugins and statusbar applets, as they will not block updating of the 
desktop while your child process runs. If you need an example of using 
g_spawn_async, take a look at the btkeyboards plugin at 
http://770.fs-security.com/keyboards.html.

Regards,
Tomas