diff --git a/ndn-cpp/c/util/ndn_realloc.c b/ndn-cpp/c/util/ndn_realloc.c
index 8e560b9..f3147f4 100644
--- a/ndn-cpp/c/util/ndn_realloc.c
+++ b/ndn-cpp/c/util/ndn_realloc.c
@@ -7,7 +7,7 @@
 #include <stdlib.h>
 #include "ndn_realloc.h"
 
-uint8_t *ndn_realloc(struct ndn_DynamicUInt8Array *self, uint8_t *array, unsigned int length)
+uint8_t *ndn_realloc(struct ndn_DynamicUInt8Array *self, uint8_t *array, size_t length)
 {
   return (uint8_t *)realloc(array, length);
 }