diff --git a/src/core/ngx_string.h b/src/core/ngx_string.h
index a1da15f..e17fc13 100644
--- a/src/core/ngx_string.h
+++ b/src/core/ngx_string.h
@@ -165,6 +165,8 @@
 uintptr_t ngx_escape_uri(u_char *dst, u_char *src, size_t size,
     ngx_uint_t type);
 void ngx_unescape_uri(u_char **dst, u_char **src, size_t size, ngx_uint_t type);
+uintptr_t ngx_escape_html(u_char *dst, u_char *src, size_t size);
+
 
 
 void ngx_sort(void *base, size_t n, size_t size,