diff --git a/asn1c/asn1c.c b/asn1c/asn1c.c
index cf1ecb9..52b909a 100644
--- a/asn1c/asn1c.c
+++ b/asn1c/asn1c.c
@@ -360,7 +360,7 @@
 		skeletons_dir);
 
 #ifdef	WIN32
-	len = target_dir_len + sizeof("/*.asn1"));
+	len = target_dir_len + sizeof("/*.asn1");
 	pattern = malloc(len);
 	assert(pattern);
 	snprintf(pattern, len, "%s/*.asn1", target_dir);