diff --git a/lib/com_err/com_err.h b/lib/com_err/com_err.h
index 16c4d9e81..03cf87e31 100644
--- a/lib/com_err/com_err.h
+++ b/lib/com_err/com_err.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997 - 2000 Kungliga Tekniska Högskolan
+ * Copyright (c) 1997 - 2001 Kungliga Tekniska Högskolan
  * (Royal Institute of Technology, Stockholm, Sweden). 
  * All rights reserved. 
  *
@@ -40,13 +40,20 @@
 
 #include <com_right.h>
 
+#if !defined(__GNUC__) && !defined(__attribute__)
+#define __attribute__(X)
+#endif
+
 typedef void (*errf) __P((const char *, long, const char *, va_list));
 
 const char * error_message __P((long));
 int init_error_table __P((const char**, long, int));
 
-void com_err_va __P((const char *, long, const char *, va_list));
-void com_err __P((const char *, long, const char *, ...));
+void com_err_va __P((const char *, long, const char *, va_list))
+    __attribute((format(printf, 3, 0)));
+
+void com_err __P((const char *, long, const char *, ...))
+    __attribute((format(printf, 3, 4)));
 
 errf set_com_err_hook __P((errf));
 errf reset_com_err_hook __P((void));