Clarify what it means to use undefined constants.

git-svn-id: https://svn.php.net/repository/phpdoc/en/trunk@130821 c90b9560-bf6c-de11-be94-00142212c4b1
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Philip Olson 2003-06-10 04:30:35 +00:00
parent 75c7e7613b
commit 9543a3e64d

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@ -1,5 +1,5 @@
<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.32 $ -->
<!-- $Revision: 1.33 $ -->
<chapter id="language.constants">
<title>Constants</title>
@ -66,10 +66,14 @@
</note>
<simpara>
If you use an undefined constant, PHP assumes that you mean
the name of the constant itself. A
<link linkend="ref.errorfunc">notice</link> will be issued
when this happens. Use the <function>defined</function>-function if
you want to know if a constant is set.
the name of the constant itself, just as if you called it as
a <type>string</type> (CONSTANT vs "CONSTANT"). An error of level
<link linkend="ref.errorfunc">E_NOTICE</link> will be issued
when this happens. See also the manual entry on why
<link linkend="language.types.array.foo-bar">$foo[bar]</link> is
wrong (unless you first <function>define</function>
<literal>bar</literal> as a constant). If you simply want to check if a
constant is set, use the <function>defined</function> function.
</simpara>
<para>
These are the differences between constants and variables: