How to prompt program error in php

In PHP, error information is an important basis for program debugging and optimization. Correctly prompting program error messages is very important for programmers. Let's explore how to prompt program errors in php.

1. Turn on error prompts

By default, php does not turn on error prompts. If we want to enable error prompts, we need to configure it in the php configuration file php.ini file. There is a parameter called "display_errors" in the php.ini file, which controls whether error messages are displayed. We can set it to:

display_errors=On

In this way, we can see error prompts in the program. Of course, we can also manually turn on the error prompt through the following code in the program:

ini_set("display_errors","On");
error_reporting(E_ALL);

2. Set the error reporting level

There are multiple error levels in php. We can set the required error reporting level according to our own needs. In the php.ini file, there is a parameter called "error_reporting", which is used to set the error reporting level. The value of this parameter can be a numeric value or an error level identifier. For example:

error_reporting= E_ALL & ~E_NOTICE & ~E_WARNING

The above code indicates that all error reports are enabled, but NOTICE and WARNING errors are filtered out. If we need to manually set the error reporting level in the program, we can use the following code:

error_reporting(E_ALL & ~E_NOTICE & ~E_WARNING);

3. Record the error log

Sometimes, we need to record error information to a log file for subsequent analysis and error finding. PHP provides a function called "error_log" that can save error information to a log file. For example:

error_log("Error message", 3, "/var/log/my-errors.log");

The above code writes the error message to /var/log/ my-errors.log file.

4. Custom error handling function

We can define our own error handling function in the program to customize error information. For example:

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

echo "<b>Error:</b> [$errno] $errstr<br>";
echo "  Fatal error on line $errline in file $errfile";
echo ", PHP " . PHP_VERSION . " (" . PHP_OS . ")<br>";
echo "Aborting...";
die();

}

set_error_handler("myErrorHandler");

In the above code, we define an own error handling function myErrorHandler and set it as PHP's default error handling function through the set_error_handler function. When an error occurs in the program, the myErrorHandler function we defined will be called.

Summary

In PHP, correctly prompting error messages is an important task for programmers to debug and optimize programs. We can prompt and handle errors by setting error prompts, setting error reporting levels, recording error logs, and customizing error handling functions. Custom error handling functions are advanced error handling methods with high flexibility and freedom.

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