Re: where is error? (Glib::spawn_async)

[Michael J M Thomson <mjmt internode on net>]

Paul Pogonyshev wrote:
> Hi.
>
> Where is error in this code fragment?
>
>       std::vector <std::string>  yelp_arguments;
>
>       yelp_arguments.push_back ("yelp");
>       yelp_arguments.push_back ("ghelp:///usr/share/gnome/help/gedit/C/gedit.xml");
>
>       try
> 	{
> 	  Glib::spawn_async (".", yelp_arguments, std::vector <std::string> (),
> 			     Glib::SPAWN_SEARCH_PATH);
> 	  return;
> 	}
>       catch (Glib::Error& exception)
> 	{
> 	  g_print ("%s...\n", exception.what ().c_str ());
> 	}
>
> I get this in terminal:
>
>     (yelp:14036): Gtk-WARNING **: cannot open display:
>
> and Yelp window is never shown.
>
> Paul
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The third argument you're passing to Glib::spawn_async(), 
std::vector<std::string>(), you shouldn't (and don't need to). It becomes the 
set of environment variables seen by the spawned child, instead of those already 
present in the parent process' environment. And while it may seem more secure or 
neater or something to change it, some variables are vital, e.g. without DISPLAY 
most Xlib-based programs won't work, and in GNOME's (and probably KDE's and 
other desktops) case there are several variables that allow session management 
and other desktop stuff to work properly. Non-GUI programs might also crap out, 
if they rely on e.g. HOME or USER (even though they shouldn't). Not sure but Mac 
OS X and probably Windows mightn't appreciate certain environment variables not 
being set properly ,either.