declare

(PHP 4, PHP 5, PHP 7)

declare �ṹ��趨һ�δ��ִ��ָ�declare ��﷨��̿��ƽṹ��ƣ�

declare (directive)
    statement

directive ��趨 declare ��ε��Ϊ��Ŀǰֻ��ʶ��ָ�ticks��Ϣ�� ticks ָ��Լ� encoding��Ϣ�� encoding ָ���

Note: encoding �� PHP 5.3.0 ��ָ�

declare ��е� statement ��ֽ��ִ��——��ִ��Լ�ִ��ʲô��ó��ȡ�� directive ��趨��ָ�

declare �ṹҲ��ȫ�ַ�Χ��Ӱ�쵽��д��루�� declare �ṹ��ļ��ļ��԰��ĸ��ļ��ã��


<?php
// these are the same:

// you can use this:
declare(ticks=1) {
    // entire script here
}

// or you can use this:
declare(ticks=1);
// entire script here
?>

Ticks

Tick��ʱ��ڣ��һ�� declare ��н��ÿִ�� N ��ɼ�ʱ�ĵͼ��ͻᷢ��¼��N ��ֵ�� declare �е� directive �� ticks=N ��ָ��ġ�

��䶼�ɼ�ʱ��ͨ��ʽ�Ͳ��ʽ��ɼ�ʱ��

��ÿ�� tick �г��ֵ��¼�� register_tick_function() ��ָ��ġ��ϸ�ڼ��ӡ�ע��ÿ�� tick �п��Գ��ֶ��¼��

Example #1 Tick ��÷�ʾ��


<?php

declare(ticks=1);

// A function called on each tick event
function tick_handler()
{
    echo "tick_handler() called\n";
}

register_tick_function('tick_handler');

$a = 1;

if ($a > 0) {
    $a += 2;
    print($a);
}

?>

Example #2 Ticks ��÷�ʾ��


<?php

function tick_handler()
{
  echo "tick_handler() called\n";
}

$a = 1;
tick_handler();

if ($a > 0) {
    $a += 2;
    tick_handler();
    print($a);
    tick_handler();
}
tick_handler();

?>

�μ� register_tick_function() �� unregister_tick_function()��

Encoding

�� encoding ָ��ÿ�νű�ָ��뷽ʽ��

Example #3 �Խű�ָ��뷽ʽ


<?php
declare(encoding='ISO-8859-1');
// code here
?>

Caution

��ռ��ʱ declare ��Ψһ�Ϸ��﷨�� declare(encoding='...');�� ... �Ǳ��ֵ�� declare(encoding='...') {} ��ռ��ʱ��

�� PHP 5.3 �г��ڱ��ʱָ�� --enable-zend-multibyte�� declare �е� encoding ֵ�ᱻ��ԡ�

ע�� phpinfo()�� PHP ��ʾ��Ƿ��ڱ��ʱָ�� --enable-zend-multibyte��

�μ� zend.script_encoding��