The Output Control functions allow you to control when output is sent from the script. This can be useful in several different situations, especially if you need to send headers to the browser after your script has began outputting data. The Output Control functions do not affect headers sent using header() or setcookie(), only functions such as echo() and data between blocks of PHP code.
Note: When upgrading from PHP 4.1.x (and 4.2.x) to 4.3.x due to a bug in earlier versions you must ensure that implict_flush is OFF in your php.ini, otherwise any output with ob_start() will not be hidden from output.
Эти функции всегда доступны.
Для использования этих функций не требуется проведение установки, поскольку они являются частью ядра PHP.
Поведение этих функций зависит от установок в php.ini.
| Name | Default | Changeable | Changelog |
|---|---|---|---|
| output_buffering | "0" | PHP_INI_PERDIR | |
| output_handler | NULL | PHP_INI_PERDIR | Available since PHP 4.0.4. |
| implicit_flush | "0" | PHP_INI_ALL | PHP_INI_PERDIR in PHP <= 4.2.3. |
Краткое разъяснение конфигурационных директив.
You can enable output buffering for all files by setting this directive to 'On'. If you wish to limit the size of the buffer to a certain size - you can use a maximum number of bytes instead of 'On', as a value for this directive (e.g., output_buffering=4096). As of PHP 4.3.5, this directive is always Off in PHP-CLI.
You can redirect all of the output of your scripts to a function. For example, if you set output_handler to mb_output_handler(), character encoding will be transparently converted to the specified encoding. Setting any output handler automatically turns on output buffering.
Note: You cannot use both mb_output_handler() with ob_iconv_handler() and you cannot use both ob_gzhandler() and zlib.output_compression.
Note: Only built-in functions can be used with this directive. For user defined functions, use ob_start().
FALSE by default. Changing this to TRUE tells PHP to tell the output layer to flush itself automatically after every output block. This is equivalent to calling the PHP function flush() after each and every call to print() or echo() and each and every HTML block.
When using PHP within an web environment, turning this option on has serious performance implications and is generally recommended for debugging purposes only. This value defaults to TRUE when operating under the CLI SAPI.
See also ob_implicit_flush().
Данное расширение не определяет никакие типы ресурсов.
Данное расширение не определяет никакие константы.
Example#1 Output Control example
<?php
ob_start();
echo "Hello\n";
setcookie("cookiename", "cookiedata");
ob_end_flush();
?>
In the above example, the output from echo() would be stored in the output buffer until ob_end_flush() was called. In the mean time, the call to setcookie() successfully stored a cookie without causing an error. (You can not normally send headers to the browser after data has already been sent.)
See also header() and setcookie().