#ifndef _ERR_H
#define _ERR_H
+#if __STDC_VERSION__ >= 201112L
+#elif defined(__GNUC__)
+#define _Noreturn __attribute__((__noreturn__))
+#else
+#define _Noreturn
+#endif
+
#include <stdarg.h>
#ifdef __cplusplus
void warnx(const char *, ...);
void vwarnx(const char *, va_list);
-void err(int, const char *, ...);
-void verr(int, const char *, va_list);
-void errx(int, const char *, ...);
-void verrx(int, const char *, va_list);
+_Noreturn void err(int, const char *, ...);
+_Noreturn void verr(int, const char *, va_list);
+_Noreturn void errx(int, const char *, ...);
+_Noreturn void verrx(int, const char *, va_list);
#ifdef __cplusplus
}