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What is the use of @ symbol in PHP
- 藏色散人Original
- 2019-01-22 16:02:2036337browse
The at symbol (@) is used as an error control operator in PHP. When an expression is appended with the @ symbol, error messages that may be generated by the expression are ignored. If the track_errors feature is enabled, the error message generated by the expression will be saved in the variable $php_errormsg. This variable is overwritten with every error.
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Example 1
<?php
// 文件错误
$file_name = @file ('non_existent_file') or
die ("Failed in opening the file: error: '$errormsg'");
// 它用于表达
$value = @$cache[$key];
//如果索引$key不存在，它将不显示通知。
?>Runtime Error:
PHP Notice: Undefined variable: errormsg in /home/fe74424b34d1adf15aa38a0746a79bed.php on line 5
Output:
Failed in opening the file: error: ''
Example 2
<?php // 语句1 $result= $hello['123'] // 语句2 $result= @$hello['123'] ?>
It will only execute Statement 1 and displays the notification message
PHP Notice: Undefined variable: hello.
NOTE: Using @ is a very bad programming practice because it doesn't make the errors go away, it just hides them, and it makes debugging harder It sucks because we can't see what's actually wrong with our code.
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