diff --git a/src/core/ngx_string.h b/src/core/ngx_string.h
index 4fe5cb6..00617f3 100644
--- a/src/core/ngx_string.h
+++ b/src/core/ngx_string.h
@@ -173,7 +173,7 @@
 
 
 void ngx_sort(void *base, size_t n, size_t size,
-    int (*cmp)(const void *, const void *));
+    ngx_int_t (*cmp)(const void *, const void *));
 #define ngx_qsort             qsort