ini_get()

(PHP 4, PHP 5, PHP 7)

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

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

参见

• get_cfg_var() 获取 PHP 配置选项的值
• ini_get_all() 获取所有配置选项
• ini_restore() 恢复配置选项的值
• ini_set() 为一个配置选项设置值

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;
  }
}
?>

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.

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.

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.

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.

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;
  }
?>

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.

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;
  }
}
?>

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.

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'.