diff --git a/main.c b/main.c
index a242d3c..138cf72 100644
--- a/main.c
+++ b/main.c
@@ -34,7 +34,7 @@
 #include <locale.h>
 #endif
 
-__RCSID("$MirOS: src/bin/mksh/main.c,v 1.237 2012/10/30 20:49:42 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/main.c,v 1.238 2012/11/12 18:28:39 tg Exp $");
 
 extern char **environ;
 
@@ -1138,7 +1138,7 @@ static void vwarningf(unsigned int, const char *, va_list)
 static void
 vwarningf(unsigned int flags, const char *fmt, va_list ap)
 {
-	if (*fmt != 1) {
+	if (fmt) {
 		if (flags & VWARNINGF_INTERNAL)
 			shf_fprintf(shl_out, "internal error: ");
 		if (flags & VWARNINGF_ERRORPREFIX)
diff --git a/sh.h b/sh.h
index bca57fc..fc52461 100644
--- a/sh.h
+++ b/sh.h
@@ -157,7 +157,7 @@
 #endif
 
 #ifdef EXTERN
-__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.600 2012/10/30 20:49:43 tg Exp $");
+__RCSID("$MirOS: src/bin/mksh/sh.h,v 1.601 2012/11/12 18:28:40 tg Exp $");
 #endif
 #define MKSH_VERSION "R40 2012/10/30"
 
@@ -1826,9 +1826,9 @@ void warningf(bool, const char *, ...)
     MKSH_A_FORMAT(__printf__, 2, 3);
 void bi_errorf(const char *, ...)
     MKSH_A_FORMAT(__printf__, 1, 2);
-#define errorfz()	errorf("\1")
-#define errorfxz(rc)	errorfx((rc), "\1")
-#define bi_errorfz()	bi_errorf("\1")
+#define errorfz()	errorf(NULL)
+#define errorfxz(rc)	errorfx((rc), NULL)
+#define bi_errorfz()	bi_errorf(NULL)
 void internal_errorf(const char *, ...)
     MKSH_A_NORETURN
     MKSH_A_FORMAT(__printf__, 1, 2);