diff --git a/lib/isc/include/isc/log.h b/lib/isc/include/isc/log.h
index 2b25979cff..68444c39dd 100644
--- a/lib/isc/include/isc/log.h
+++ b/lib/isc/include/isc/log.h
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: log.h,v 1.12 2000/03/04 00:43:40 tale Exp $ */
+/* $Id: log.h,v 1.13 2000/03/04 16:41:14 tale Exp $ */
 
 #ifndef ISC_LOG_H
 #define ISC_LOG_H 1
@@ -727,6 +727,10 @@ isc_log_categorybyname(isc_log_t *lctx, const char *name);
  * Notes:
  *	The string name of a category is not required to be unique.
  *
+ * Requires:
+ *	lctx is a valid context.
+ *	name is not NULL.
+ *
  * Returns:
  *	A pointer to the _first_ isc_logcategory_t structure used by "name".
  *
@@ -741,6 +745,10 @@ isc_log_modulebyname(isc_log_t *lctx, const char *name);
  * Notes:
  *	The string name of a module is not required to be unique.
  *
+ * Requires:
+ *	lctx is a valid context.
+ *	name is not NULL.
+ *
  * Returns:
  *	A pointer to the _first_ isc_logmodule_t structure used by "name".
  *
diff --git a/lib/isc/log.c b/lib/isc/log.c
index 7b5e5309de..ef436868d9 100644
--- a/lib/isc/log.c
+++ b/lib/isc/log.c
@@ -15,7 +15,7 @@
  * SOFTWARE.
  */
 
-/* $Id: log.c,v 1.19 2000/03/04 00:43:38 tale Exp $ */
+/* $Id: log.c,v 1.20 2000/03/04 16:39:54 tale Exp $ */
 
 /* Principal Authors: DCL */
 
@@ -531,6 +531,7 @@ isc_log_categorybyname(isc_log_t *lctx, const char *name) {
 	isc_logcategory_t *catp;
 
 	REQUIRE(VALID_CONTEXT(lctx));
+	REQUIRE(name != NULL);
 
 	for (catp = lctx->categories; catp->name != NULL; catp++)
 		if (catp->id == UINT_MAX)
@@ -585,6 +586,7 @@ isc_log_modulebyname(isc_log_t *lctx, const char *name) {
 	isc_logmodule_t *modp;
 
 	REQUIRE(VALID_CONTEXT(lctx));
+	REQUIRE(name != NULL);
 
 	for (modp = lctx->modules; modp->name != NULL; modp++)
 		if (modp->id == UINT_MAX)