php教程

ini_get

(PHP 4, PHP 5, PHP 7)

ini_get — 获取一个配置选项的值

说明

ini_get ( string $varname ) : string

成功时返回配置选项的值。

参数

varname

配置选项名称。

返回值

成功是返回配置选项值的字符串，null 的值则返回空字符串。如果配置选项不存在，将会返回 FALSE。

范例

Example #1 一些 ini_get() 例子

<?php
/*
我们的 php.ini 包含了以下的设置：

display_errors = On
register_globals = Off
post_max_size = 8M
*/

echo 'display_errors = ' . ini_get('display_errors') . "\n";
echo 'register_globals = ' . ini_get('register_globals') . "\n";
echo 'post_max_size = ' . ini_get('post_max_size') . "\n";
echo 'post_max_size+1 = ' . (ini_get('post_max_size')+1) . "\n";
echo 'post_max_size in bytes = ' . return_bytes(ini_get('post_max_size'));

function return_bytes($val) {
    $val = trim($val);
    $last = strtolower($val[strlen($val)-1]);
    switch($last) {
        // 自 PHP 5.1.0 起可以使用修饰符 'G'
        case 'g':
            $val *= 1024;
        case 'm':
            $val *= 1024;
        case 'k':
            $val *= 1024;
    }

    return $val;
}

?>

以上例程的输出类似于：


display_errors = 1
register_globals = 0
post_max_size = 8M
post_max_size+1 = 9
post_max_size in bytes = 8388608

注释

Note: 当查询一个 boolean 值

一个 off 的 boolean ini 值将会以空字符串或者 "0" 返回；on 的 ini 值会以 "1" 返回。 此函数也会返回 INI 值的文字字符串。

Note: 当查询一个内存尺寸的值

许多内存尺寸的 ini 值，类似 upload_max_filesize 是以简写表示法储存在 php.ini 文件里。 ini_get() 会返回 php.ini 文件中储存的确切字符串，而不是它的等量 integer。 尝试对这些值使用常规算术运算函数将不会得到预期的结果。 以上例子显示了转换简写表示法为字节的一种方式，和 PHP 源码所做的比较像。

Note:

ini_get() 无法读取 "array" 的 ini 选项，例如 pdo.dsn.*，在这个例子中会返回 FALSE 。

更新日志

版本 说明
5.3.0 当配置项不存在，之前会返回空字符串，现在会返回 FALSE。

参见

User Contributed Notes

IceNV 05-Jun-2017 08:53
Be aware that max_execution_time can be altered by XDebug.

While debugging a script locally that made use of <?php ini_get('max_execution_time'); ?> it returned 0 when XDebug remote debugging was enabled and the IDE was listening to it.

It makes sense, since debugging manually takes time so we don't want the script to time out ; but in that particular case, it made it look to the script like max_execution_time was 0, so calculations were wrong.

You can see in phpinfo() that local value is 0 in that case, but master value is the correct one you set in your php.ini.
bishop at php dot net 02-Sep-2015 07:52
In a similar vein, converting flags to booleans proper:

<?php
function return_boolean($val)
{
    static $map = array ('on' => true, 'true' => true, 'off' => false, 'false' => false);
    return @($map[strtolower($val)] ?: (bool)$val);
}
?>

If you're using PHP >= 7, consider replacing ?: with ?? and removing the @ silencer.
bishop@php 02-Sep-2015 07:37
Yet another implementation of return_bytes:

<?php
function return_bytes($val)
{
    assert('1 === preg_match("/^\d+([kmg])?$/i", $val)');
    static $map = array ('k' => 1024, 'm' => 1048576, 'g' => 1073741824);
    return (int)$val * @($map[strtolower(substr($val, -1))] ?: 1);
}
?>

If you're using PHP >= 7, you might replace ?: with ?? to avoid the use of the @ silencer.
Ivo Mandalski 15-Nov-2011 08:27
This version of return_bytes takes care of the MB, GB, KB cases along with the M,G,K ones.
Hope this is helpful!

<?php
    public static function return_bytes ($val)
    {
        if(empty($val))return 0;

        $val = trim($val);

        preg_match('#([0-9]+)[\s]*([a-z]+)#i', $val, $matches);

        $last = '';
        if(isset($matches[2])){
            $last = $matches[2];
        }

        if(isset($matches[1])){
            $val = (int) $matches[1];
        }

        switch (strtolower($last))
        {
            case 'g':
            case 'gb':
                $val *= 1024;
            case 'm':
            case 'mb':
                $val *= 1024;
            case 'k':
            case 'kb':
                $val *= 1024;
        }

        return (int) $val;
    }
?>
Stas Trefilov, OpteamIS 26-Mar-2010 10:08
another version of return_bytes which returns faster and does not use multiple multiplications (sorry:). even if it is resolved at compile time it is not a good practice;
no local variables are allocated;
the trim() is omitted (php already trimmed values when reading php.ini file);
strtolower() is replaced by second case which wins us one more function call for the price of doubling the number of cases to process (may slower the worst-case scenario when ariving to default: takes six comparisons instead of three comparisons and a function call);
cases are ordered by most frequent goes first (uppercase M-values being the default sizes);
specs say we must handle integer sizes so float values are converted to integers and 0.8G becomes 0;
'Gb', 'Mb', 'Kb' shorthand byte options are not implemented since are not in specs, see
http://www.php.net/manual/en/faq.using.php#faq.using.shorthandbytes

<?php
function return_bytes ($size_str)
{
    switch (substr ($size_str, -1))
    {
        case 'M': case 'm': return (int)$size_str * 1048576;
        case 'K': case 'k': return (int)$size_str * 1024;
        case 'G': case 'g': return (int)$size_str * 1073741824;
        default: return $size_str;
    }
}
?>
nicolas dot grekas+php at gmail dot com 19-Aug-2009 10:51
Here is how to accurately test for boolean php.ini values:

<?php

function ini_get_bool($a)
{
    $b = ini_get($a);

    switch (strtolower($b))
    {
    case 'on':
    case 'yes':
    case 'true':
        return 'assert.active' !== $a;

    case 'stdout':
    case 'stderr':
        return 'display_errors' === $a;

    default:
        return (bool) (int) $b;
    }
}

?>
peter 29-Jul-2008 02:25
The above example function called return_bytes() assumes that ini_get('upload_max_filesize') delivers only one letter at the end. As I've seen 'Mb' and things like that, I'd suggest to change the $last = ... part into $last = strtolower(substr($val,strlen($val/1),1)).
I'd call it $unit then.
filh at filh dot org 21-Nov-2005 06:24
Concerning the value retourned, it depends on how you set it.
I had the problem with horde-3 which test the safe_mode value.
THan :
- if you set the value with php_admin_value safe_mode Off (or On) ini_get returns the string
- if you set the value with php_admin_flag safe_mode Off (or On) ini_get returns the boolean.
david dot tulloh at infaze dot com dot au 21-Jun-2005 07:01
You can set custom entries in the ini file to provide globals such as database details.
However these must be retrieved with get_cfg_var, ini_get won't work.
Der Graph 16-Aug-2004 11:59
It might be useful for included scripts that include other files to extend the 'include_path' variable:

<?php ini_set('include_path',ini_get('include_path').':../includes:');  ?>

Sometimes, it may also be useful to store the current 'include_path' in a variable, overwrite it, include, and then restore the old 'include_path'.

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