__compiletime_error
extern void __compiletime_error("value doesn't fit into mask")
# define __compiletime_error(msg) __attribute__((__error__(msg)))
# define __compiletime_error(msg)
extern void __compiletime_error("copy source size is too small")
extern void __compiletime_error("value doesn't fit into mask")
# define __compiletime_error(message) __attribute__((error(message)))
# define __compiletime_error(message)