diff --git a/lib/libc/other/getsubopt.c b/lib/libc/other/getsubopt.c
index 765f59562..b50ee6649 100644
--- a/lib/libc/other/getsubopt.c
+++ b/lib/libc/other/getsubopt.c
@@ -54,8 +54,8 @@ getsubopt(optionp, tokens, valuep)
 	int cnt;
 	char *p;
 
-	_DIAGASSERT(tokens != NULL);
-	_DIAGASSERT(valuep != NULL);
+	assert(tokens != NULL);
+	assert(valuep != NULL);
 	/* optionp is tested below */
 
 	suboptarg = *valuep = NULL;