How to avoid error log entries?

[jeffg]

I was looking through my Apache error log and came across lines such as the following:

[error] [client 192.168.1.2] PHP Notice:  Undefined index:  cancel in C:\\Apache\\htdocs\\login.php on line 83, referer: http://vcwb/index.html

This is the line that causes it:

if ($_POST['cancel']){	do_cancel();}elseif ($_POST['login'])....

I do this sort of thing all the time to check whether something has been clicked (or whatever). Is there a better way of writing this code so it doesn't post the warning?

[justsomeguy]

if (isset($_POST['cancel']))If you also want to check the value:if (isset($_POST['cancel']) && $_POST['cancel'] == true)

[jeffg]

if (isset($_POST['cancel']))

Is this going to fix the error log entry, or is it just complaining that the key 'cancel' does not exist in the $_POST array? I assumed the latter.

[justsomeguy]

Yeah, it's complaining that you are trying to access a key that doesn't exist. If you check using isset first then you won't get that notice.

[jeffg]

if (isset($_POST['cancel']))If you also want to check the value:if (isset($_POST['cancel']) && $_POST['cancel'] == true)

I have sooo many references to POST and SESSION variables, that rather than inflate my code by doing this everywhere, I have created a file varcheck.inc with the following:

<?php// varcheck.inc// Checks variables are set before accessfunction post($index){	$ret = false;	if (isset($_POST["$index"]))		$ret = $_POST["$index"];	return $ret;}function session($index){	$ret = false;	if (isset($_SESSION["$index"]))		$ret = $_SESSION["$index"];	return $ret;}?>

and have replaced all my references to $_POST['index'] with post('index'), and the same for $_SESSION. Maybe takes a bit more time to process, but at least it was quick to change, and avoids all those errors in Apache's error log.