describe the ap_log_error(...,ap_server_conf,...) idiom

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1082933 13f79535-47bb-0310-9956-ffa450edef68

diff --git a/docs/manual/developer/new_api_2_4.xml b/docs/manual/developer/new_api_2_4.xml
index 7a5feccd011f3bad7861aa3bb3bb46e535226c3a..15e98d84c063e31bfd1b3313da3169fb0e3a9166 100644 (file)
--- a/docs/manual/developer/new_api_2_4.xml
+++ b/docs/manual/developer/new_api_2_4.xml
@@ -286,6 +286,18 @@
        <code>ap_log_*</code> without additional wrappers. In this way, the
        code will remain compatible with HTTPD 2.0 and 2.2.</p>
 
+    <p>A <code>server_rec</code> pointer must be passed to 
+       <code>ap_log_error()</code> when called after startup.  This
+       was always appropriate, but there are even more limitations with
+       a <code>NULL</code> <code>server_rec</code> in 2.4 than in
+       previous releases.  Beginning with 2.3.12, the global variable
+       <code>ap_server_conf</code> can always be used as
+       the <code>server_rec</code> parameter, as it will be
+       <code>NULL</code> only when it is valid to pass <code>NULL</code>
+       to <code>ap_log_error()</code>.  <code>ap_server_conf</code>
+       should be used only when a more appropriate <code>server_rec</code>
+       is not available.</p> 
+
     <p>Consider the following changes to take advantage of the new
        <code>APLOG_TRACE1..8</code> log levels:</p>
        <ul>