documented the new ngx.config.prefix() API function.

README

@@ -5583,6 +5583,20 @@ Nginx API for Lua
 
     This field was first introduced in the 0.8.7.
 
+  ngx.config.prefix
+    syntax: *prefix = ngx.config.prefix()*
+
+    context: *set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*,
+    header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*,
+    init_by_lua**
+
+    Returns the Nginx server "prefix" path, as determined by the "-p"
+    command-line option when running the nginx executable, or the path
+    specified by the "--prefix" command-line option when building Nginx with
+    the "./configure" script.
+
+    This function was first introduced in the 0.9.2.
+
   ndk.set_var.DIRECTIVE
     syntax: *res = ndk.set_var.DIRECTIVE_NAME*
 

README.markdown

@@ -167,6 +167,7 @@ Table of Contents
     * [ngx.on_abort](#ngxon_abort)
     * [ngx.timer.at](#ngxtimerat)
     * [ngx.config.debug](#ngxconfigdebug)
+    * [ngx.config.prefix](#ngxconfigprefix)
     * [ndk.set_var.DIRECTIVE](#ndkset_vardirective)
     * [coroutine.create](#coroutinecreate)
     * [coroutine.resume](#coroutineresume)
@@ -5653,6 +5654,19 @@ This field was first introduced in the `0.8.7`.
 
 [Back to TOC](#table-of-contents)
 
+ngx.config.prefix
+-----------------
+
+**syntax:** *prefix = ngx.config.prefix()*
+
+**context:** *set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*, init_by_lua**
+
+Returns the Nginx server "prefix" path, as determined by the `-p` command-line option when running the nginx executable, or the path specified by the `--prefix` command-line option when building Nginx with the `./configure` script.
+
+This function was first introduced in the `0.9.2`.
+
+[Back to TOC](#table-of-contents)
+
 ndk.set_var.DIRECTIVE
 ---------------------
 **syntax:** *res = ndk.set_var.DIRECTIVE_NAME*

doc/HttpLuaModule.wiki

@@ -4806,6 +4806,16 @@ This boolean field indicates whether the current Nginx is a debug build, i.e., b
 
 This field was first introduced in the <code>0.8.7</code>.
 
+== ngx.config.prefix ==
+
+'''syntax:''' ''prefix = ngx.config.prefix()''
+
+'''context:''' ''set_by_lua*, rewrite_by_lua*, access_by_lua*, content_by_lua*, header_filter_by_lua*, body_filter_by_lua*, log_by_lua*, ngx.timer.*, init_by_lua*''
+
+Returns the Nginx server "prefix" path, as determined by the <code>-p</code> command-line option when running the nginx executable, or the path specified by the <code>--prefix</code> command-line option when building Nginx with the <code>./configure</code> script.
+
+This function was first introduced in the <code>0.9.2</code>.
+
 == ndk.set_var.DIRECTIVE ==
 '''syntax:''' ''res = ndk.set_var.DIRECTIVE_NAME''