Learn about PHP error levels and error reporting options

Understand PHP error levels and error reporting options

When writing PHP programs, you often encounter various errors, including syntax errors, runtime errors, etc. In order to be able to detect and debug these errors promptly, it is important to understand PHP error levels and error reporting options. This article details PHP's error levels and how to set error reporting options.

PHP Error Level

PHP defines different error levels to represent the severity of the error. These error levels are represented by the following constants:

• E_ERROR: Fatal error , will cause the script to terminate execution.
• E_WARNING: Non-fatal error that will cause the script to continue execution, but may produce incorrect results.
• E_PARSE: Parsing error will cause the script to terminate execution.
• E_NOTICE: prompts an error and will not affect the execution of the script.
• E_DEPRECATED: Warn about deprecated features.
• E_STRICT: Provides coding suggestions and considerations.

In addition to the common error levels mentioned above, there are several other error levels available. For ease of use, PHP provides a combination of error level constants:

• E_ALL: Displays all errors and warnings.
• E_ALL & ~E_NOTICE: Display all errors and warnings, but exclude prompt errors.

Set error reporting options

In PHP, set error reporting options through the error_reporting() function. This function parameter can accept an error level constant or an error level integer value.

The sample code is as follows:

// 设置错误报告级别为 E_ALL
error_reporting(E_ALL);

// 设置错误报告级别为 E_ALL & ~E_NOTICE
error_reporting(E_ALL & ~E_NOTICE);

// 打开错误输出
ini_set('display_errors', 1);

// 关闭错误输出
ini_set('display_errors', 0);

In the above code, the error reporting level is set to E_ALL by calling the error_reporting() function. Then, use the ini_set() function to turn on or off error output. When setting display_errors to 1, error messages will be output to the screen; when set to 0, error messages will not be displayed.

In addition to using functions to set error reporting options, you can also configure them in the php.ini file. In the php.ini file, there is an error_reporting option that can be used to set the error reporting level.

error_reporting = E_ALL

; or

error_reporting = E_ALL & ~E_NOTICE

When the PHP code encounters an error when running, it will decide whether to display the error message based on the set error reporting level. Development environments are typically set up to display all errors and warnings so that problems can be discovered and debugged promptly. In a production environment, you should try to avoid displaying error messages to protect the security and stability of the system.

Summary

By understanding PHP’s error levels and error reporting options, we can better debug and handle errors when writing PHP programs. By setting the appropriate error reporting level, errors can be discovered and fixed in time, improving the robustness and reliability of the code.

Hope this article helps you understand PHP error levels and error reporting options.

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