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Doc Bug #13577 is_null evaluates true for non-existent variables
Submitted: 2001-10-06 15:41 UTC Modified: 2002-06-10 05:15 UTC
From: sander@php.net Assigned:
Status: Closed Package: Documentation problem
PHP Version: 4.0.6 OS: Win2K & Debian Linux
Private report: No CVE-ID: None
View Developer Edit
 [2001-10-06 15:41 UTC] sander@php.net 
is_null() evaluates true for non-existent variables. Consider the following snippet:

unset($foo);
if(is_null($foo))
  echo 'true';
else
  echo 'false';

It outputs 'true'.

Can this be fixed before 4.0.7?

Patches

Pull Requests

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2001-10-06 20:29 UTC] sniper@php.net 
Intented behaviour. Not a bug.
 [2001-10-07 07:10 UTC] sander@php.net 
If it's intended, then it should be documented.
Reopened as a documentation problem.
 [2001-10-07 09:57 UTC] jeroen@php.net 
An uninitialized variable equals NULL. So it _is_ null.

This should be in the language.types.null section.
 [2002-06-10 05:15 UTC] mfischer@php.net 
This bug has been fixed in CVS. You can grab a snapshot of the
CVS version at http://snaps.php.net/. In case this was a documentation 
problem, the fix will show up soon at http://www.php.net/manual/.
In case this was a PHP.net website problem, the change will show
up on the PHP.net site and on the mirror sites.
Thank you for the report, and for helping us make PHP better.
 
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