diff --git a/src/http/modules/ngx_http_browser_module.c b/src/http/modules/ngx_http_browser_module.c
index 95cab49..f774254 100644
--- a/src/http/modules/ngx_http_browser_module.c
+++ b/src/http/modules/ngx_http_browser_module.c
@@ -222,7 +222,7 @@
     { ngx_string("ancient_browser"), NULL, ngx_http_browser_variable,
       NGX_HTTP_ANCIENT_BROWSER, NGX_HTTP_VAR_CHANGEABLE, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_fastcgi_module.c b/src/http/modules/ngx_http_fastcgi_module.c
index 741e577..ea16eca 100644
--- a/src/http/modules/ngx_http_fastcgi_module.c
+++ b/src/http/modules/ngx_http_fastcgi_module.c
@@ -631,7 +631,7 @@
       ngx_http_fastcgi_path_info_variable, 0,
       NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_NOHASH, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_geoip_module.c b/src/http/modules/ngx_http_geoip_module.c
index 8e151aa..5ea4f5f 100644
--- a/src/http/modules/ngx_http_geoip_module.c
+++ b/src/http/modules/ngx_http_geoip_module.c
@@ -232,7 +232,7 @@
       ngx_http_geoip_city_int_variable,
       offsetof(GeoIPRecord, area_code), 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index 61bf55c..b42839c 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -829,7 +829,7 @@
       ngx_http_proxy_internal_chunked_variable, 0,
       NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_NOHASH, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_realip_module.c b/src/http/modules/ngx_http_realip_module.c
index e1839e6..7d3f2a9 100644
--- a/src/http/modules/ngx_http_realip_module.c
+++ b/src/http/modules/ngx_http_realip_module.c
@@ -122,7 +122,7 @@
     { ngx_string("realip_remote_port"), NULL,
       ngx_http_realip_remote_port_variable, 0, 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_ssi_filter_module.c b/src/http/modules/ngx_http_ssi_filter_module.c
index b09ce20..e29e173 100644
--- a/src/http/modules/ngx_http_ssi_filter_module.c
+++ b/src/http/modules/ngx_http_ssi_filter_module.c
@@ -321,7 +321,7 @@
     { ngx_string("date_gmt"), NULL, ngx_http_ssi_date_gmt_local_variable, 1,
       NGX_HTTP_VAR_NOCACHEABLE, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_ssl_module.c b/src/http/modules/ngx_http_ssl_module.c
index b466e5d..4370275 100644
--- a/src/http/modules/ngx_http_ssl_module.c
+++ b/src/http/modules/ngx_http_ssl_module.c
@@ -329,7 +329,7 @@
     { ngx_string("ssl_client_v_remain"), NULL, ngx_http_ssl_variable,
       (uintptr_t) ngx_ssl_get_client_v_remain, NGX_HTTP_VAR_CHANGEABLE, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/modules/ngx_http_stub_status_module.c b/src/http/modules/ngx_http_stub_status_module.c
index 61199f2..9bdf881 100644
--- a/src/http/modules/ngx_http_stub_status_module.c
+++ b/src/http/modules/ngx_http_stub_status_module.c
@@ -76,7 +76,7 @@
     { ngx_string("connections_waiting"), NULL, ngx_http_stub_status_variable,
       3, NGX_HTTP_VAR_NOCACHEABLE, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index fb32092..6a2b322 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -427,7 +427,7 @@
     { ngx_string("upstream_cookie_"), NULL, ngx_http_upstream_cookie_variable,
       0, NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_PREFIX, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index fbc9ffa..afeb4ce 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -376,7 +376,7 @@
     { ngx_string("arg_"), NULL, ngx_http_variable_argument,
       0, NGX_HTTP_VAR_NOCACHEABLE|NGX_HTTP_VAR_PREFIX, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/http/ngx_http_variables.h b/src/http/ngx_http_variables.h
index df337de..f3f7f3c 100644
--- a/src/http/ngx_http_variables.h
+++ b/src/http/ngx_http_variables.h
@@ -43,6 +43,8 @@
     ngx_uint_t                    index;
 };
 
+#define ngx_http_null_variable  { ngx_null_string, NULL, NULL, 0, 0, 0 }
+
 
 ngx_http_variable_t *ngx_http_add_variable(ngx_conf_t *cf, ngx_str_t *name,
     ngx_uint_t flags);
diff --git a/src/http/v2/ngx_http_v2_module.c b/src/http/v2/ngx_http_v2_module.c
index 032abcb..7f7dab2 100644
--- a/src/http/v2/ngx_http_v2_module.c
+++ b/src/http/v2/ngx_http_v2_module.c
@@ -225,7 +225,7 @@
     { ngx_string("http2"), NULL,
       ngx_http_v2_variable, 0, 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_http_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_geoip_module.c b/src/stream/ngx_stream_geoip_module.c
index f694033..6507b71 100644
--- a/src/stream/ngx_stream_geoip_module.c
+++ b/src/stream/ngx_stream_geoip_module.c
@@ -210,7 +210,7 @@
       ngx_stream_geoip_city_int_variable,
       offsetof(GeoIPRecord, area_code), 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_stream_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_realip_module.c b/src/stream/ngx_stream_realip_module.c
index 1266605..57b1ac2 100644
--- a/src/stream/ngx_stream_realip_module.c
+++ b/src/stream/ngx_stream_realip_module.c
@@ -89,7 +89,7 @@
     { ngx_string("realip_remote_port"), NULL,
       ngx_stream_realip_remote_port_variable, 0, 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_stream_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_ssl_module.c b/src/stream/ngx_stream_ssl_module.c
index da26a41..010b98b 100644
--- a/src/stream/ngx_stream_ssl_module.c
+++ b/src/stream/ngx_stream_ssl_module.c
@@ -273,7 +273,7 @@
     { ngx_string("ssl_client_v_remain"), NULL, ngx_stream_ssl_variable,
       (uintptr_t) ngx_ssl_get_client_v_remain, NGX_STREAM_VAR_CHANGEABLE, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_stream_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_ssl_preread_module.c b/src/stream/ngx_stream_ssl_preread_module.c
index 2040b4f..e3d11fd 100644
--- a/src/stream/ngx_stream_ssl_preread_module.c
+++ b/src/stream/ngx_stream_ssl_preread_module.c
@@ -85,7 +85,7 @@
     { ngx_string("ssl_preread_server_name"), NULL,
       ngx_stream_ssl_preread_server_name_variable, 0, 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_stream_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_upstream.c b/src/stream/ngx_stream_upstream.c
index c9e1784..7feac43 100644
--- a/src/stream/ngx_stream_upstream.c
+++ b/src/stream/ngx_stream_upstream.c
@@ -100,7 +100,7 @@
       ngx_stream_upstream_bytes_variable, 1,
       NGX_STREAM_VAR_NOCACHEABLE, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_stream_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_variables.c b/src/stream/ngx_stream_variables.c
index 5d15f3a..45d6e60 100644
--- a/src/stream/ngx_stream_variables.c
+++ b/src/stream/ngx_stream_variables.c
@@ -111,7 +111,7 @@
     { ngx_string("protocol"), NULL,
       ngx_stream_variable_protocol, 0, 0, 0 },
 
-    { ngx_null_string, NULL, NULL, 0, 0, 0 }
+      ngx_stream_null_variable
 };
 
 
diff --git a/src/stream/ngx_stream_variables.h b/src/stream/ngx_stream_variables.h
index 8155111..4ead2a6 100644
--- a/src/stream/ngx_stream_variables.h
+++ b/src/stream/ngx_stream_variables.h
@@ -43,6 +43,8 @@
     ngx_uint_t                    index;
 };
 
+#define ngx_stream_null_variable  { ngx_null_string, NULL, NULL, 0, 0, 0 }
+
 
 ngx_stream_variable_t *ngx_stream_add_variable(ngx_conf_t *cf, ngx_str_t *name,
     ngx_uint_t flags);