PHP ob_start() 函数

示例

创建输出缓冲区：

<?php
ob_start();
echo "This content will not be sent to the browser.";
ob_end_clean();

echo "This content will be sent to the browser.";
?>

亲自试一试 »

定义和用法

这个ob_start()函数创建一个输出缓冲区。可以传入一个回调函数，在缓冲区的内容从缓冲区中刷新之前对缓冲区的内容进行处理。标志可用于允许或限制缓冲区能够执行的操作。

语法

ob_start(callback, chunk_size, flags);

参数值

Parameter

Description

callback

Optional. A callback used to process the contents of the buffer before it gets flushed.

The callback function should have the following parameters:

Parameter	Description
buffer	The contents of the output buffer
phase	A bitmask which may have any number of the following flags: PHP_OUTPUT_HANDLER_START - If the output buffer was just created PHP_OUTPUT_HANDLER_FLUSH - If the output buffer is currently being flushed PHP_OUTPUT_HANDLER_FINAL - If the output buffer will be deleted right after this operation

chunk_size

Optional. Defaults to 0. When set to a value greater than zero, the buffer will automatically be flushed as soon as the length of the contents exceeds this value

flags

Optional. Defaults to PHP_OUTPUT_HANDLER_STDFLAGS.

A bitmask which determines what operations the buffer is permitted to do. It may contain the following flags:

PHP_OUTPUT_HANDLER_CLEANABLE - Calls to ob_clean(), ob_end_clean() and ob_get_clean() are permitted.

PHP_OUTPUT_HANDLER_FLUSHABLE - Calls to ob_flush(), ob_end_flush() and ob_get_flush() are permitted.

PHP_OUTPUT_HANDLER_REMOVABLE - Calls to ob_end_clean(), ob_end_flush() and ob_get_flush() are permitted.

PHP_OUTPUT_HANDLER_STDFLAGS - Equivalent to

PHP_OUTPUT_HANDLER_CLEANABLE|
PHP_OUTPUT_HANDLER_FLUSHABLE|
PHP_OUTPUT_HANDLER_REMOVABLE

技术细节

返回值：	TRUE 成功，FALSE 失败
PHP 版本：	4+

❮ PHP 输出控制函数