src/lib/id.h

#ifndef LIB_ID_H
#define LIB_ID_H
 
/*
 * Widget id pool (internal).
 *
 * Public Widget.id values come from here. 0 is reserved for the window
 * page and is never allocated. Recycled ids go onto a free list so a
 * destroyed widget’s id can be reused.
 *
 * libAllocId is called from the API/main thread when creating a handle
 * to return to the app. libFreeId is called from the worker when a node
 * is destroyed. One mutex covers both.
 */
 
/* Create the mutex and empty free list. Returns 0 or -1. */
int idPoolInit(void);
 
/* Tear down the pool. Does not walk the widget tree. */
void idPoolDestroy(void);
 
/*
 * Next unused id, or a recycled one. Returns 0 if the pool is dead or
 * unsigned short would wrap (treat as failure; do not use as a widget).
 */
unsigned short libAllocId(void);
 
/* Return id to the free list. id 0 is ignored. */
void libFreeId(unsigned short id);
 
#endif