Preferences structure definition

typedef struct {
  int skeletonData;
} Prefs;
Prefs prefs;

Open preferences

void startApp() {
  Int16 prefSize = sizeof(Prefs);
  if ((PrefGetAppPreferences (AppCreator,
           1000, // pref database id
           &prefs,
           &prefSize,
            true) // saved during Hotsync
    == noPreferenceFound)
    || (prefSize != sizeof(Prefs))) {
          // default initialization, since discovered
          // Prefs was missing or old.
    prefs.skeletonData=1;
  }
}

Write preferences

void stopApp() {
  PrefSetAppPreferences (AppCreator,
        1000,  // pref database id
        1,   // version of pref database
        &prefs,
        sizeof(Prefs),
        true);  // saved during hotsync
}