Usage of php get_defined_constants() function

This article mainly introduces the usage of the get_defined_constants function in php. The example analyzes the function, definition and usage skills of the get_defined_constants function. Friends in need can refer to the following

The example in this article describes the usage of get_defined_constants function in php. Share it with everyone for your reference. The specific analysis is as follows:

get_defined_constants (PHP 4 > = 4.1.0, PHP 5)

get_defined_constants - Returns an associated

array with the names of all Constants and their values ​​

Description

Array get_defined_constants ([boolean $collocation])

Returns the names and values ​​of all The currently defined constant. This includes extensions set up and define() functions created.

Parameters

Category

Causes this function to return the multidimensional array with the first item dimension and constant in the category and their values ​​in the second dimension .

<?php
define("MY_CONSTANT", 1);
print_r(get_defined_constants(true));
?> 
The above example will output something similar to:
Array
(
  [internal] => Array
    (
      [E_ERROR] => 1
      [E_WARNING] => 2
      [E_PARSE] => 4
      [E_NOTICE] => 8
      [E_CORE_ERROR] => 16
      [E_CORE_WARNING] => 32
      [E_COMPILE_ERROR] => 64
      [E_COMPILE_WARNING] => 128
      [E_USER_ERROR] => 256
      [E_USER_WARNING] => 512
      [E_USER_NOTICE] => 1024
      [E_ALL] => 2047
      [TRUE] => 1
    )
  [pcre] => Array
    (
      [PREG_PATTERN_ORDER] => 1
      [PREG_SET_ORDER] => 2
      [PREG_OFFSET_CAPTURE] => 256
      [PREG_SPLIT_NO_EMPTY] => 1
      [PREG_SPLIT_DELIM_CAPTURE] => 2
      [PREG_SPLIT_OFFSET_CAPTURE] => 4
      [PREG_GREP_INVERT] => 1
    )
  [user] => Array
    (
      [MY_CONSTANT] => 1
    )
)

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