diff --git a/src/libraries/libmisc/s-string.h b/src/libraries/libmisc/s-string.h
index 04d3c852a237ef54c77bfc94c391cd679c3da4ed..18a5b96228d326acda51e6c6caf32223ee9f4688 100644
--- a/src/libraries/libmisc/s-string.h
+++ b/src/libraries/libmisc/s-string.h
@@ -130,9 +130,9 @@ s_crea_str (String	* dest_string,
  */
 
 extern  Success
-s_mem_crea_str (String	    * dest_string,
-	    	const char  * buffer,
-	    	String_size   length);
+s_mem_crea_str (String	    	     * dest_string,
+	    	const unsigned char  * buffer,
+	    	String_size   	       length);
 
 /*
  * Create a string of a given size. The contents of the string