Description: ------------ When using strict errorhandling HTML_Progress fails on line 500. Because ob_end_clean want to clean a still empty buffer. This is solved by using a @ in front of ob_end_clean, but it still throws a E_NOTICE. Developers enabling this error level will not be able to run HTML_Progress. From the php manual about the function ob_end_clean : If the function fails it generates an E_NOTICE fix: use ob_get_clean() instead of ob_get_contents. old: $bar = ob_get_contents(); $bar .= $this->_lineEnd; @ob_end_clean(); new: $bar = ob_get_clean(); $bar .= $this->_lineEnd; Reproduce code: --------------- error_reporting(E_ALL); function php_error_handler($errno, $errstr, $errfile, $errline) { die("$errstr in $errfile at line $errline: $errstr"); } set_error_handler('php_error_handler'); require_once ('HTML/Progress/BarHorizontal.php'); $pkg = array('PEAR', 'Config'); $bar = new HTML_Progress_Bar_Horizontal(); for ($i=0; $i<2; $i++) { $bar->display(50); echo "installing package ... : ". $pkg[$i] ."<br /> \n"; } Expected result: ---------------- Cool progressing bar.. Actual result: -------------- ob_end_clean() [ref.outcontrol]: failed to delete buffer. No buffer to delete. in /usr/lib/php/HTML/Progress.php at line 590: ob_end_clean() [ref.outcontrol]: failed to delete buffer. No buffer to delete.