add errmsg API

errmsg.h

@@ -0,0 +1,27 @@
+#ifndef ERRMSG_H
+#define ERRMSG_H
+
+#ifdef __dietlibc__
+#include <sys/cdefs.h>
+#else
+#define __attribute__(x)
+#endif
+
+/* These use file descriptor 2, not buffer_2!
+ * Call buffer_flush(buffer_2) before calling these! */
+
+extern const char* argv0;
+
+void errmsg_iam(const char* who);	/* set argv0 */
+
+/* terminate with NULL. */
+/* newline is appended automatically. */
+void errmsg_warn(const char* message, ...);
+void errmsg_warnsys(const char* message, ...);
+
+#define carp(...) errmsg_warn(__VA_ARGS__,0)
+#define carpsys(...) errmsg_warnsys(__VA_ARGS__,0)
+#define die(n,...) { errmsg_warn(__VA_ARGS__,0); exit(n); }
+#define diesys(n,...) { errmsg_warnsys(__VA_ARGS__,0); exit(n); }
+
+#endif