transformation

    </code></p></div>

    <p>The number of parameters of the <code>ap_log_*</code> functions and the

       definition of <code>APLOG_MARK</code> has changed. Normally, the change

       is completely transparent. However, if a module implements wrapper

       functions for <code>ap_log_*</code> and uses <code>APLOG_MARK</code>

       when calling these wrappers, some adjustments are necessary.

       The easiest way is for the module to define and use a different macro

       that expands to the parameters required by the log wrapper functions.

       <code>APLOG_MARK</code> should only be used when calling

       <code>ap_log_*</code> without additional wrappers. In this way, the

       code will remain compatible with HTTPD 2.0 and 2.2.</p>

       is completely transparent. However, changes are required if a

       module uses <code>APLOG_MARK</code> as a parameter to its own functions

       or if a module calls <code>ap_log_*</code> without passing

       <code>APLOG_MARK</code>.  A module which uses wrappers

       around <code>ap_log_*</code> typically uses both of these constructs.</p>

    <p>The easiest way to change code which passes <code>APLOG_MARK</code> to

       its own functions is to define and use a different macro that expands to

       the parameters required by those functions, as <code>APLOG_MARK</code>

       should only be used when calling <code>ap_log_*</code>

       directly.  In this way, the code will remain compatible with HTTPD 2.0

       and 2.2.</p>

    <p>Code which calls <code>ap_log_*</code> without passing 

       <code>APLOG_MARK</code> will necessarily differ between 2.4 and earlier

       releases, as 2.4 requires a new third argument,

       <code>APLOG_MODULE_INDEX</code>.</p>

    <div class="example"><p><code>

       /* code for httpd 2.0/2.2 */<br />

       ap_log_perror(file, line, APLOG_ERR, 0, p, "Failed to allocate dynamic lock structure");<br />

       <br />

       /* code for httpd 2.4 */<br />

       ap_log_perror(file, line, APLOG_MODULE_INDEX, APLOG_ERR, 0, p, "Failed to allocate dynamic lock structure");<br />

       <br />

    </code></p></div>

    <p>A <code>server_rec</code> pointer must be passed to 

       <code>ap_log_error()</code> when called after startup.  This