ob_get_level

    (PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)

    ob_get_level — 返回输出缓冲机制的嵌套级别

    说明

    ob_get_level(): int

    返回输出缓冲机制的嵌套级别。

    参数

    此函数没有参数。

    返回值

    返回嵌套的输出缓冲处理程序的级别；或者是，如果输出缓冲区不起作用，返回零。

    警告

    ob_get_level() 和 ob_get_status() 之间相同级别的值相差 1。对于 ob_get_level()，第一级为 1。而对于 ob_get_status()，第一级为 0。

    参见

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    用户贡献的备注 3 notes

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    55
    Anonymous
    12 years ago
    For users confused about getting "1" as a return value from ob_get_level at the beginning of a script: this likely means the PHP ini directive "output_buffering" is not set to off / 0. PHP automatically starts output buffering for all your scripts if this directive is not off (which acts as if you called ob_start on the first line of your script).

    If your scripts may end up on any server and you don't want end-users to have to configure their INI, you can use the following at the start of your script to stop output buffering if it's already started:
    <?php
    if (ob_get_level()) ob_end_clean();
    ?>

    Alternatively, you can use the opposite if you always want to have an output buffer at the start of your script:
    <?php
    if (!ob_get_level()) ob_start();
    ?>
    up
    10
    Anonymous
    9 years ago
    This can be used to handle exceptions properly when using output buffering for rendering a view which may or may not be using output buffering

    <?php

    function getView($view)
    {
    $level = ob_get_level();

    ob_start();

    try
    {
    include     $view;
    }

    catch (    Exception $e)
    {
    while (    ob_get_level() > $level)
    {
    ob_end_clean();
    }

    throw     $e;
    }

    return     ob_get_clean();
    }
    up
    2
    bonzini at gnu dot org
    20 years ago
    Even under older PHP, you can decide if output buffering is active (i.e. ob_get_level() > 0) using

    <?php $ob_active = ob_get_length () !== FALSE ?>

    Paolo
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