virtual() is an Apache-specific function which is similar to <!--#include virtual...--> in mod_include. It performs an Apache sub-request. It is useful for including CGI scripts or .shtml files, or anything else that you would parse through Apache. Note that for a CGI script, the script must generate valid CGI headers. At the minimum that means it must generate a Content-type header.
To run the sub-request, all buffers are terminated and flushed to the browser, pending headers are sent too.
This function is only supported when PHP is installed as an Apache module.
The query string can be passed to the included file but $_GET is copied from the parent script and only $_SERVER['QUERY_STRING'] is filled with the passed query string. The query string may only be passed when using Apache 2. The requested file will not be listed in the Apache access log.
Note: Environment variables set in the requested file are not visible to the calling script.
Note: As of PHP 4.3.3 you can use this function with the NSAPI server module in Netscape/iPlanet/SunONE webservers, too.