有什么方法可以显示或抛出PHP警告? [英] Is there any way to show, or throw, a PHP warning?

问题描述

我在数据库类中有一个select()方法，该方法具有可选的布尔参数$sum.此参数用于说明该方法是否应该也使用COUNT(*).

I have a select() method in a database class, that has an optional boolean argument $sum. This argument is used to say if the method should use COUNT(*) or not too.

如果未设置属性(例如，当我使用$sum == false调用select()时)尝试访问$class->sum，我想显示警告，就像那些普通的PHP错误一样.

I would like to show a warning, like those normal PHP errors, if I try to access $class->sum if the attribute is not set (i.e. when I call select() with $sum == false.

有什么办法可以显示这样的警告，还是我应该回显一个错误并感到高兴?

Is there any way to show a warning like this, or I should just echo an error and be happy?

推荐答案

如果要生成警告，则应编写

If you want to generate a warning, you should write

trigger_error($yourErrorMessage, E_USER_WARNING);

trigger_error() 具有$error_type参数，用于设置错误级别(Notice，Warning或Fatal error).常量分别是:

trigger_error() has the $error_type parameter for setting the error level (Notice, Warning or Fatal error). The constants are, respectively:

E_USER_NOTICE             // Notice (default)
E_USER_WARNING            // Warning
E_USER_ERROR              // Fatal Error

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请注意，Fatal error停止了后续PHP代码的执行，而Notice和Warning使其继续执行.

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Note that Fatal error stops the execution of subsequent PHP code, while Notice and Warning let it continue.

从PHP 5.5开始，您还应考虑最后语句.

From PHP 5.5, you should also consider the Finally statement.

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