(PHP 4 >= 4.1.0, PHP 5)
get_defined_constants — Returns an associative array with the names of all the constants and their values
Returns the names and values of all the constants currently defined. This includes those created by extensions as well as those created with the define() function.
Causing this function to return a multi-dimensional
array with categories in the keys of the first dimension and constants
and their values in the second dimension.
以上例程的输出类似于：
<?php
define("MY_CONSTANT", 1);
print_r(get_defined_constants(true));
?>
Array
(
[Core] => 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
)
)
| 版本 | 说明 |
|---|---|
| 5.3.1 | Windows only: Core constants are categorized under Core, previously mhash. |
| 5.3.0 | Core constants are categorized under Core, previously internal. On Windows, the Core Constants are categorized under mhash. |
| 5.2.11 | The categorize parameter now operates appropriately. Previously, the categorize parameter was interpreted as !is_null($categorize), making any value other than NULL force the constants to be categorized. |
| 5.0.0 | The categorize parameter was added. |
Example #1 get_defined_constants() Example 以上例程的输出类似于：
<?php
print_r(get_defined_constants());
?>
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
)