extern int vsprintf(char *buf, const char *, va_list);
extern int snprintf(char * buf, size_t size, const char * fmt, ...)
__attribute__ ((format (printf, 3, 4)));
extern int vsnprintf(char *buf, size_t size, const char *fmt, va_list args);
extern int scnprintf(char * buf, size_t size, const char * fmt, ...)
__attribute__ ((format (printf, 3, 4)));
extern int vscnprintf(char *buf, size_t size, const char *fmt, va_list args);
extern int sscanf(const char *, const char *, ...)
__attribute__ ((format (scanf,2,3)));
extern int vsscanf(const char *, const char *, va_list);