diff --git a/ash/output.c b/ash/output.c
index 30ec72c..444e30a 100644
--- a/ash/output.c
+++ b/ash/output.c
@@ -116,7 +116,7 @@
 
 void
 out1str(p)
-	char *p;
+	const char *p;
 	{
 	outstr(p, out1);
 }
@@ -124,7 +124,7 @@
 
 void
 out2str(p)
-	char *p;
+	const char *p;
 	{
 	outstr(p, out2);
 }
@@ -132,7 +132,7 @@
 
 void
 outstr(p, file)
-	register char *p;
+	register const char *p;
 	register struct output *file;
 	{
 	while (*p)
diff --git a/ash/output.h b/ash/output.h
index 42321c0..441ee8c 100644
--- a/ash/output.h
+++ b/ash/output.h
@@ -56,9 +56,9 @@
 
 
 #ifdef __STDC__
-void outstr(char *, struct output *);
-void out1str(char *);
-void out2str(char *);
+void outstr(const char *, struct output *);
+void out1str(const char *);
+void out2str(const char *);
 void outfmt(struct output *, char *, ...);
 void out1fmt(char *, ...);
 void fmtstr(char *, int, char *, ...);