Programming PHP

web server and clears the buffer, but doesn’t terminate output buffering. The flush( )
function not only flushes and clears the output buffer, but also tries to make the web
server send the data to the browser immediately. The ob_end_flush( ) function sends
the output data to the web server and ends output buffering. In all cases, if you specified
a callback with ob_start( ), that function is called to decide exactly what gets
sent to the server.
If your script ends with output buffering still enabled (that is, if you haven’t called
ob_end_flush( ) or ob_end_clean( )), PHP calls ob_end_flush( ) for you.
The following code collects the output of the phpinfo( ) function and uses it to determine
whether you have the PDF module installed:
ob_start( );
phpinfo( );
$phpinfo = ob_get_contents( );
ob_end_clean( );
if (strpos($phpinfo, "module_pdf") === FALSE) {
echo "You do not have PDF support in your PHP, sorry.";
} else {
echo "Congratulations, you have PDF support!";
}
Of course, a quicker and simpler approach to check if a certain extension is available
is to pick a function that you know the extension provides and check if it exists. For
the PDF extension, you might do:
if (function_exists('pdf_begin_page'))
To change all references in a document from http://www.yoursite.com/ to http://
www.mysite.com/, simply wrap the page like this:
Visit our site now!
Visit our site now!
Another way to do this is with a callback. Here, the rewrite( ) callback changes the
text of the page: