diff --git a/src/util/error.c b/src/util/error.c
index e2d5408e..34e4c88f 100644
--- a/src/util/error.c
+++ b/src/util/error.c
@@ -52,7 +52,7 @@ er(int bell, int shall_sleep, unsigned char *fmt, va_list params)
 }
 
 int errline;
-unsigned char *errfile;
+const unsigned char *errfile;
 
 void
 elinks_debug(unsigned char *fmt, ...)
diff --git a/src/util/error.h b/src/util/error.h
index 4b56b51d..a97c921b 100644
--- a/src/util/error.h
+++ b/src/util/error.h
@@ -11,7 +11,7 @@
 /* This errfile thing is needed, as we don't have var-arg macros in standart,
  * only as gcc extension :(. */
 extern int errline;
-extern unsigned char *errfile;
+extern const unsigned char *errfile;
 
 /* @DBG(format_string) is used for printing of debugging information. It
  * should not be used anywhere in the official codebase (although it is often