[maemo-developers] [maemo-developers] TZ environment variable in desktop application

[From: Simon Budig]

Hi all.

As some of you know, I am writing a applet for the statusbar that simply
displays a clock. It turns out that this is not exactly easy...

For some reason the TZ environment variable is set inside the
maemo_af_desktop application (which is the process the statusbar applets
run in). Unfortunately it seems to be set to a nonsensical value (for me
it was something like "8#\x14A", where \x14 stands for chr(0x14)) which
gets interpreted as "GMT" by functions like localtime() etc.

So currently I do this to determine the time:

  /* unset TZ */
  tz_str = g_strdup (g_getenv ("TZ"));
  g_unsetenv ("TZ");

  gettimeofday (&tv, NULL);
  time_info = localtime (&tv.tv_sec);

  /* restore TZ */
  g_setenv ("TZ", tz_str, FALSE);
  g_free (tz_str);

and I wonder how the desktop clock applet from nokia manages to display
the correct time.

Can somebody shed some light on this? Is it really necessary that the
desktop application messes with TZ? Is the "8#\x14A"-value anything
useful? Can I omit the restoring without messing anything up?

BTW.: The clock application crashes when setting the timezone and/or
time. Is this bug known?

Oh, and a kind of announcement: the current version of the status bar
clock uses the trick above to determine the time correctly, reacts on
clicks with the pen (as requested by some people on IRC) and should do
correct power management:
   http://www.home.unix-ag.org/simon/files/n770/panelclock_0.3_arm.deb

Bye,
         Simon

-- 
              simon at budig.de              http://simon.budig.de/