魔术常量

一些魔术常量会根据使用位置而变化。例如 __LINE__ 的值取决于它在脚本中使用的行。所有这些“魔术”常量都在编译时解析,而常规常量则在运行时解析。这些特殊的常量不区分大小写,如下:

PHP 的魔术常量
名字 说明
__LINE__ 文件中的当前行号。
__FILE__ 文件的完整路径和文件名。如果用在被包含文件中,则返回被包含的文件名。
__DIR__ 文件所在的目录。如果用在被包括文件中,则返回被包括的文件所在的目录。它等价于 dirname(__FILE__)。除非是根目录,否则目录中名不包括末尾的斜杠。
__FUNCTION__ 当前函数的名称。匿名函数则为 {closure}
__CLASS__ 当前类的名称。类名包括其被声明的作用域(例如 Foo\Bar)。当用在 trait 方法中时,__CLASS__ 是调用 trait 方法的类的名字。
__TRAIT__ Trait 的名字。Trait 名包括其被声明的作用域(例如 Foo\Bar)。
__METHOD__ 类的方法名。
__PROPERTY__ 仅在属性挂钩内有效。等同于属性的名称。
__NAMESPACE__ 当前命名空间的名称。
ClassName::class 完整的类名。

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用户贡献的备注 6 notes

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3
theking2 at king dot ma
3 years ago
If PHP is run inside a web server request there is an important difference between the __DIR__ constant and $_SERVER['DOCUMENT_ROOT'].

Where __DIR__ of a PHP script contained within a sub-folder will include the complete server path $_SERVER['DOCUMENT_ROOT'] will contain a server path up to the _root_ of the application. This can be helpful when for instance an auto-loader is defined in an include file sitting inside a sub-folder and where the classes are located in another folder at the root of the application.
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2
chris at ocproducts dot com
2 years ago
Note that __CLASS__ and __METHOD__ both reference the class the code is written in, not whatever the object class is. E.g. if you have an object of class B inheriting from class A, any usage of __CLASS__ in class A is going to give "A".
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1
webmaster at event-horizon dot lt
17 days ago
I have got this script:
<?=
$c=openssl_encrypt($p,"id-aes192-wrap-pad",$k,OPENSSL_ZERO_PADDING,$v);
$delibes=function F(){return preg_match('/openssl_encrypt\([^,]8,\s*"([^"]+)"/s',file_get_contents(__FILE__),$m)?$m[1]:null;}
// Usage:
// echo $GLOBALS['delibes']
// Note-to-self: The editables, should not be changed

I have no idea how to change __FILE__, perhaps using __DIR__."but what is the relative path?"
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0
Athralon dot media at gmail dot com
9 days ago
This is a magic constant: "but what is the relative path?"
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0
dirk at biztechwiz dot com
12 days ago
Getting the magic constants from the right place is important.  For example, creating a function to log location information requires explicit inclusion.

<?php
/***********
* magic_constants_include.php
*
* Magic constant test include file
*/
function showInclude($file=__FILE__, $lineno=__LINE__) {
    echo "Parameter values: $file ($lineno)\n";
    echo "Local constants: " . __FILE__ . "; " . __LINE__ . "\n";
}
?>

<?php
/************
* magic_constants_test.php
*/

require_once 'magic_constants_include.php';

echo "Function call with parameter defaults:\n";
showInclude();

echo "Function call with parameter explicit magic constants:\n";
showInclude(__FILE__, __LINE__);
?>

Results:
php -f magic_constants_test.php
Function call with parameter defaults:
Parameter values: /home/dirk/project/dirk/php/magic_constants_include.php (7)
Local constants: /home/dirk/project/dirk/php/magic_constants_include.php; 9
Function call with parameter explicit magic constants:
Parameter values: /home/dirk/project/dirk/php/magic_constants_test.php (12)
Local constants: /home/dirk/project/dirk/php/magic_constants_include.php; 9
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-3
webmaster at event-horizon dot lt
17 days ago
For example, I used the magic constant
"Whats' the name of this card holder?"

And found out, the answer is "John & Jane Doe"
Now we have banking in Sweden.
Swedish female programmer.
Inventor of programming.
Using technique 1+2, allowed: 0

I recommend you to do this, too.

So, the magic constant for implementing LUIGI-characters is.
"IS THIS MY GAME?"
And you could go ask duck.ai, what the answer to that is.
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