Texas Instruments TI89 Developer Guide - Page 102

60 Chapter 7: Flash Application Layout 7.3.4.2. This app can be deleted if Target app does not exist or Target app is not running BOOL candelete(pFrame self) { Access_AMS_Global_Variables; AppID targetID = EV_getAppID(TargetApp); return targetID == H_NULL || (targetID != EV_appA && targetID != EV_appB); } How Localization Works Applications call XR_stringPtr to look up a string given a string number. When XR_stringPtr looks up a string, it starts with the frame pointed to by the ACB (Application Control Block) of the currently executing application (app identified by EV_currentApp). The prototype chain of the object frame is searched for the given string number. An unsuccessful search of the prototype chain tries again with the prototype chain of the frame's parent and ultimately to the system frame. A language localizer app installs a new language by adding a new frame of strings at the head of the target app's object chain. Here is how app frames are linked together before a localizer is installed. 0 0 system frame ACB 0 app attributes & strings Figure 7.3: Linked App Frames The above figure illustrates an app frame with a parent link but no prototype link. A string search would begin with the app frame then proceed to the system frame. After installing a localizer, the ACB is redirected to point first to the localizer frame. TI-89 / TI-92 Plus Developer Guide Not for Distribution Beta Version January 26, 2001