П О Р Т А Л                            
С Е Т Е В Ы Х                          
П Р О Е К Т О В                        
  
Поиск по сайту:
                                                 
Главная

О проекте

Web-мастеру
     HTML & JavaScript
     SSI
     Perl
     PHP
     XML & XSLT
     Unix Shell

MySQL

Безопасность

Хостинг

Другое








Самое читаемое:

Учебник PHP - "Для Чайника".
Просмотров 174965 раз(а).

Иллюстрированный самоучитель по созданию сайтов.
Просмотров 71902 раз(а).

Учебник HTML.
Просмотров 72037 раз(а).

Руководство по PHP5.
Просмотров 42645 раз(а).

Хостинг через призму DNS.
Просмотров 49118 раз(а).

Подборка текстов стандартных документов.
Просмотров 43058 раз(а).

Учебник PHP - Самоучитель
Просмотров 49403 раз(а).

Документация на MySQL (учебник & справочное руководство)
Просмотров 49639 раз(а).

Внешние атаки...
Просмотров 40198 раз(а).

Учебник PHP.
Просмотров 35219 раз(а).

SSI в примерах.
Просмотров 26516 раз(а).



 
 
| Добавить в избранное | Сделать стартовой | Помощь




Руководство по PHP
Пред. Глава 16. Control Structures След.

declare

The declare construct is used to set execution directives for a block of code. The syntax of declare is similar to the syntax of other flow control constructs:

declare (directive)
statement

The directive section allows the behavior of the declare block to be set. Currently only one directive is recognized: the ticks directive. (See below for more information on the ticks directive)

The statement part of the declare block will be executed -- how it is executed and what side effects occur during execution may depend on the directive set in the directive block.

The declare construct can also be used in the global scope, affecting all code following it.

<?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

A tick is an event that occurs for every N low-level statements executed by the parser within the declare block. The value for N is specified using ticks=N within the declare blocks's directive section.

The event(s) that occur on each tick are specified using the register_tick_function(). See the example below for more details. Note that more than one event can occur for each tick.

Пример 16-3. Profile a section of PHP code

<?php
// A function that records the time when it is called
function profile($dump = FALSE)
{
    static
$profile;

    
// Return the times stored in profile, then erase it
    
if ($dump) {
        
$temp = $profile;
        unset(
$profile);
        return
$temp;
    }

    
$profile[] = microtime();
}

// Set up a tick handler
register_tick_function("profile");

// Initialize the function before the declare block
profile();

// Run a block of code, throw a tick every 2nd statement
declare(ticks=2) {
    for (
$x = 1; $x < 50; ++$x) {
        echo
similar_text(md5($x), md5($x*$x)), "<br />;";
    }
}

// Display the data stored in the profiler
print_r(profile(TRUE));
?>
The example profiles the PHP code within the 'declare' block, recording the time at which every second low-level statement in the block was executed. This information can then be used to find the slow areas within particular segments of code. This process can be performed using other methods: using ticks is more convenient and easier to implement.

Ticks are well suited for debugging, implementing simple multitasking, background I/O and many other tasks.

See also register_tick_function() and unregister_tick_function().



Если Вы не нашли что искали, то рекомендую воспользоваться поиском по сайту:
 





Copyright © 2005-2016 Project.Net.Ru