Screen Private

Screen Private is X jargon for devPrivate (an array of values) attached to a Screen data structure. These arrays are sized dynamically at server startup and reset. Each array is actually a union (DevUnion) of common useful types (pointer, long and unsigned long). Screen Privates contains data that is accessed by several routines in the driver. Since an X server may be driving many graphics adapters during its execution, each physical screen is allocated a ScreenRec(D4nfb) structure. Your driver hangs its own data structure off the bottom of this structure. The template graphics driver created with xmkddx contains code to allocate and use your driver's Screen Private. The structure is allocated in the xxxInit.c file and defined in the xxxDefs.h file, which also includes a simple macro that gives quick access to the driver's Screen Private. As you write your driver, feel free to add and remove data from this structure according to your needs.