...is there a way around it, perhaps by the PHP version of "error handling", etc.?
I know that unlink will simply return a value of false (0) if the delete is unsuccessful, however (at least in my case) it will also generate a PHP error message of "permission denied", evidently because the user still has that document (a PDF generated by the pdftk.exe executable) open in the browser.
I need some way, if possible, to know in advance if the unlink is going to be unsuccesful, or otherwise a way to simply skip the unlink operation, without an error message, if it will be unsuccessful. Any ideas?