diff --git a/src/core/ngx_resolver.c b/src/core/ngx_resolver.c
index ade5005..15181da 100644
--- a/src/core/ngx_resolver.c
+++ b/src/core/ngx_resolver.c
@@ -81,6 +81,7 @@
 static void ngx_resolver_timeout_handler(ngx_event_t *ev);
 static void ngx_resolver_free_node(ngx_resolver_t *r, ngx_resolver_node_t *rn);
 static void *ngx_resolver_alloc(ngx_resolver_t *r, size_t size);
+static void *ngx_resolver_calloc(ngx_resolver_t *r, size_t size);
 static void ngx_resolver_free(ngx_resolver_t *r, void *p);
 static void ngx_resolver_free_locked(ngx_resolver_t *r, void *p);
 static void *ngx_resolver_dup(ngx_resolver_t *r, void *src, size_t size);
@@ -1813,7 +1814,7 @@
 }
 
 
-void *
+static void *
 ngx_resolver_calloc(ngx_resolver_t *r, size_t size)
 {
     u_char  *p;
diff --git a/src/core/ngx_resolver.h b/src/core/ngx_resolver.h
index b1b8ede..e513c39 100644
--- a/src/core/ngx_resolver.h
+++ b/src/core/ngx_resolver.h
@@ -138,7 +138,6 @@
 void ngx_resolve_name_done(ngx_resolver_ctx_t *ctx);
 ngx_int_t ngx_resolve_addr(ngx_resolver_ctx_t *ctx);
 void ngx_resolve_addr_done(ngx_resolver_ctx_t *ctx);
-void *ngx_resolver_calloc(ngx_resolver_t *r, size_t size);
 char *ngx_resolver_strerror(ngx_int_t err);