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Bug #50068 const problem
Submitted: 2009-11-03 20:16 UTC Modified: 2009-11-04 13:48 UTC
From: jachym dot tousek at gmail dot com Assigned:
Status: Not a bug Package: Scripting Engine problem
PHP Version: 5.3.1RC3 OS: Windows 7
Private report: No CVE-ID: None
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 [2009-11-03 20:16 UTC] jachym dot tousek at gmail dot com
const is not working

Reproduce code:
const ROOT_DIR = __DIR__ . '/..'; //parse error

define('ROOT_DIR',__DIR__ . '/..'); //works fine


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 [2009-11-03 21:11 UTC]
I think this behavior is by design. const expressions are evaluated at compile time. So only few operations are supported in a const expression and string concatenation is not one of those. I could repro this in PHP 5.2 (after putting it under a class).
 [2009-11-03 21:46 UTC]
Thank you for taking the time to write to us, but this is not
a bug. Please double-check the documentation available at and the instructions on how to report
a bug at

 [2009-11-03 22:26 UTC] jachym dot tousek at gmail dot com
Well i've checked [] and also updated from 5.3.0 to 5.3.1RC3 before sending this report, but there is nothing about const name = 'value'; being different from define('name','value'); and i can not understand it even now.
 [2009-11-04 01:44 UTC]
const is a compile time constant and only allows simple scalar values.

define is a constant resolved at runtime and it allows full expressions when being defined.
 [2009-11-04 13:48 UTC] jachym dot tousek at gmail dot com
OK i get it now, but still it should be in documentation.
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