 <p>You can add functions to Studio by putting PHP files with stub function descriptions into special directory. Find this directory in filesystem in a following way: write something like gmdate(), select the name and press F3. You will be taken to one of the prototype files. Note the directory where this file resides (shown on the top and if you hover over the tab). Now you need to create stubs for functions you are missing just like the one you're looking at. You can put them into any file, generally, but I suggest putting them into separate file - like geoip.php - and put this file into that directory. You may also want to do right-click/Show In/PHP Explorer and browse other prototype files if you need examples of how to do it right. </p>