c_mem_safety/handle.h

#ifndef MAG_HANDLE_H
#define MAG_HANDLE_H
/* Simple single-header library that makes you have RAII in gcc (also works in C++ compilers) */
/* Licence: CC-BY */

/** Tells your constructor/destructor handler function about the state */
enum HANDLE_STATE {
	HANDLE_CREAT,
	HANDLE_DESTR
};

#ifndef __cplusplus

#define creat(TNAME, VNAME, VINIT) \
	[[gnu::always_inline]] inline void VNAME##_cleanuper(struct TNAME *v) { \
		TNAME##_lifetime_handler(HANDLE_DESTR, v, NULL); \
	} \
	[[gnu::cleanup(VNAME##_cleanuper)]] struct TNAME VNAME; \
	TNAME##_lifetime_handler(HANDLE_CREAT, & VNAME, VINIT);

#define handle(TNAME) \
	static inline void TNAME##_lifetime_handler( \
		enum HANDLE_STATE state, \
		struct TNAME *self, \
		void *data)

#else /* C++ compilers better be able to compile code written with us */

#define creat(TNAME, VNAME, VINIT) \
	TNAME##_raiicpp VNAME(VINIT);

#define handle(TNAME) \
	struct TNAME##_raiicpp; \
	static inline void TNAME##_lifetime_handler( \
		enum HANDLE_STATE state, \
		struct TNAME##_raiicpp *self, \
		void *data); \
	struct TNAME##_raiicpp : public TNAME { \
		inline TNAME##_raiicpp(void *data) { \
			TNAME##_lifetime_handler(HANDLE_CREAT, this, data); \
		} \
		inline ~TNAME##_raiicpp() { \
			TNAME##_lifetime_handler(HANDLE_DESTR, this, nullptr); \
		} \
	}; \
	static inline void TNAME##_lifetime_handler( \
		enum HANDLE_STATE state, \
		struct TNAME##_raiicpp *self, \
		void *data)

#endif /* __cplusplus */
/*
 * EXAMPLE:
 *
 * struct Meaning {
 * 		int a;
 * 		int b;
 * };
 * // You should not typedef this EVER!
 *
 * handle(Meaning) {
 * 	if(state == HANDLE_CREAT) {
 * 		self->a = *(int*) data;
 * 		self->b = 2;
 * 	} else {
 * 		printf("%d\n", self->a + self->b);
 * 	}
 * }
 *
 * // Now you can use a handle in your local scopes
 * // Should print 42:
 * int main() {
 * 		int initializer = 40;
 * 		creat(Meaning, d, &initializer);
 * }
 *
 * Rem.: Unrelated trick, but you can typedef struct A A; // both typedef and forward declare
 */
#endif /* MAG_HANDLE_H */