Настройка во время выполнения
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.
- output_buffering boolean/integer
-
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.
- output_handler string
-
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.
Замечание: You cannot use both mb_output_handler() with ob_iconv_handler() and you cannot use both ob_gzhandler() and zlib.output_compression.
Замечание: Only built-in functions can be used with this directive. For user defined functions, use ob_start().
- implicit_flush boolean
-
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().
Коментарии
Using "OFF" or no value on output_buffering will disable header modifications, like redirects or content-type or content-disposition resulting in the error we commonly attribute to output before header modifications:
Warning: Cannot modify header information - headers already sent by (output started at C:\PATH\filename.php:1) C:\PATH\filename.php on line 1
Example code with output_buffering = OFF which results in this behavior. Changing it to "ON" or giving it a value will likely cause normal behavior.
<?php header("Location: http://www.php.net"); ?>
or
<?php header("Content-Type: text/Calendar"); ?>
<?php header("Content-Disposition: inline; filename=appointment.ics"); ?>