diff --git a/src/tree_schema_helpers.c b/src/tree_schema_helpers.c
index 64f8945..b402ce3 100644
--- a/src/tree_schema_helpers.c
+++ b/src/tree_schema_helpers.c
@@ -58,7 +58,7 @@
 }
 
 LY_ERR
-lysp_check_date(struct lys_parser_ctx *ctx, const char *date, uint8_t date_len, const char *stmt)
+lysp_check_date(struct lys_parser_ctx *ctx, const char *date, size_t date_len, const char *stmt)
 {
     struct tm tm, tm_;
     char *r;