Descriptionint virtual ( string filename)
virtual() is an Apache-specific function which is equivalent 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.