How to write error message in php

As PHP becomes more and more popular, website operators and developers must pay more and more attention to PHP error prompts. When an error occurs on a website, it becomes crucial to quickly locate the problem and fix it. Properly written error messages can help improve the readability and maintainability of PHP code. In this article, we will introduce how to write error prompts in PHP to help you manage and maintain your PHP code more easily.

What is the error message?

When writing PHP code, you may encounter a variety of errors, such as syntax errors, runtime errors, and logic errors. An error message is a mechanism that provides the developer with information about the error and the type of error when an error occurs. In PHP, error prompts can be configured through the error_reporting() and ini_set() functions. The error_reporting() function is used to set the error reporting level of PHP, and the ini_set() function is used to set the error reporting output method of a specific level.

PHP error reporting levels include the following levels:

• E_ERROR: Fatal error, stopping script execution.
• E_WARNING: Warns, but does not stop script execution.
• E_NOTICE: Prompt, warning developers to pay attention to problems in the code.
• E_STRICT: Prompts developers to use newer versions of PHP for better performance and maintainability.
• E_DEPRECATED: Prompts developers that some features are obsolete or deprecated.
• E_ALL: Display all types of errors.

In order to avoid displaying error messages to clients in a production environment, we can set the error prompt to E_ALL & ~E_NOTICE to ignore notification-level errors.

How to write PHP error prompts

In PHP, we can use the following methods to write error prompts:

1. Use the die() function

This function is used to send a message and stop script execution. For example:

if (!file_exists('file.txt')) {

die('File does not exist');

}

This will output "File does not exist" and stop script execution.

2. Using the trigger_error() function

This function is used to generate an error message and send it to the runtime error handler. For example:

$x = 10;
if ($x > 5) {

trigger_error('x cannot be more than 5');

}

This will generate the following error message:

Notice: x cannot be more than 5 in file.php on line 3

Please note that regardless of the error level, it can be used in the trigger_error() function.

3. Use try-catch block

When we use try-catch block, if an exception occurs, it will jump to the catch block and use the Error message to prompt the developer. For example:

try {

$x = 1/0;

} catch(Exception $e) {

echo 'Caught exception: '.$e->getMessage();

}

will output the following message:

Caught exception: Division by zero

4. Using error handlers

We can use the set_error_handler() function to set a custom error handler. This function will be called automatically when an error occurs in the code. For example:

function custom_error_handler($errno, $errstr, $errfile, $errline) {

echo '<b>Custom error:</b> ' .$errstr.' at '.$errfile.' on line '.$errline;

}

set_error_handler('custom_error_handler');

$x = 10/0;

This will generate the following error message:

Custom error: Division by zero at file.php on line 9

Error handler allowed We customize the format and style of error messages. This is also a coding technique for maintainability and good readability.

Conclusion

Correctly writing error prompts is the key to PHP development. It can help us quickly locate errors in the code. You can use different methods to implement error prompts, such as die() function, trigger_error() function, try-catch block and error handler. Please note that the error level should be reasonably selected based on the actual situation. Finally, through correct error prompts, we can improve the readability and maintainability of the code, thereby ensuring the stability and reliability of the PHP code.

The above is the detailed content of How to write error message in php. For more information, please follow other related articles on the PHP Chinese website!