The usage of constant in php is [constant(constant)]. The constant in parentheses specifies the name of the constant to be checked. If this constant is undefined, the function returns NULL.
The operating environment of this article: windows10 system, php 7.3, thinkpad t480 computer.
There is a function constant in php. This function can return the value of a constant. If the constant is not defined, it returns NULL. Some friends may not understand this function. Let's take a look at the usage of this function.
Function syntax:
constant(constant)
The constant here is the name of the constant to be checked.
Code example:
<!DOCTYPE html>
<html>
<body>
<?php
//define a constant
define("GREETING","Hello you! How are you today?");
echo constant("GREETING");
?>
</body>
</html> The running effect is as follows:
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