How to Write to an Error Log File in PHP

When we have a large-scale web application running on production mode, we need to monitor all the errors or potential errors that a user can face. The best way to keep a close eye on all the possible errors is by logging them into a file whenever there is an error.

This article will introduce the built-in function error_log() and write error logs in a file in PHP.

Write to an Error Log File in PHP

PHP has a built-in function error_log() that sends an error message to the defined error handling. We can easily log errors and warning into a PHP script file and change the configuration from PHP’s php.ini file.

The error_log() function takes in 3 arguments.

The first argument is the error we want to save into a file, and the second is the error message type. We usually use 3 as a message type to save the error messages to a file.

The third argument is the file’s location in which we want to save the error logs.

So, let’s go through an example. We’ll create an error and save it into a file using the error_log() function.

# php
$error = "A new error is occured";
$path = "application-errors.log";
error_log($error, 3, $path);

Output:

From the above example, the error has been saved into a file. By using error_log() in every function, we can log the errors in a file and ensure that the code works perfectly.

In addition, we can also send the time of the error to make sure when a specific error has occurred.