--- /dev/null
+#ifndef _ERR_H
+#define _ERR_H
+
+#include <stdarg.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+void warn(const char *, ...);
+void vwarn(const char *, va_list);
+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);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
--- /dev/null
+#include <err.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+
+void vwarn(const char *fmt, va_list ap)
+{
+ vfprintf(stderr, fmt, ap);
+ perror("");
+}
+
+void vwarnx(const char *fmt, va_list ap)
+{
+ vfprintf(stderr, fmt, ap);
+ putc('\n', stderr);
+}
+
+void verr(int status, const char *fmt, va_list ap)
+{
+ vwarn(fmt, ap);
+ exit(status);
+}
+
+void verrx(int status, const char *fmt, va_list ap)
+{
+ vwarnx(fmt, ap);
+ exit(status);
+}
+
+void warn(const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ vwarn(fmt, ap);
+ va_end(ap);
+}
+
+void warnx(const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ vwarnx(fmt, ap);
+ va_end(ap);
+}
+
+void err(int status, const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ verr(status, fmt, ap);
+ va_end(ap);
+}
+
+void errx(int status, const char *fmt, ...)
+{
+ va_list ap;
+ va_start(ap, fmt);
+ verrx(status, fmt, ap);
+ va_end(ap);
+}