如何在 PHP 中写入错误日志文件

If you don't want to change anything in your php.ini file, according to PHP documentation, you can do this.

error_log("Error message\n", 3, "/mypath/php.log");

The first parameter is the string to be sent to the log. The second parameter 3 means expect a file destination. The third parameter is the log file path.

You can use normal file operation to create an error log. Just refer this and input this link: PHP File Handling

you can simply use :

error_log("your message");

By default, the message will be send to the php system logger.

We all know that PHP save errors in php_errors.log file.

But, that file contains a lot of data.

If we want to log our application data, we need to save it to a custom location.

We can use two parameters in the error_log function to achieve this.

http://php.net/manual/en/function.error-log.php

We can do it using:

error_log(print_r($v, TRUE), 3, '/var/tmp/errors.log');

Where,

print_r($v, TRUE) : logs $v (array/string/object) to log file. 3: Put log message to custom log file specified in the third parameter.

'/var/tmp/errors.log': Custom log file (This path is for Linux, we can specify other depending upon OS).

OR, you can use file_put_contents()

file_put_contents('/var/tmp/e.log', print_r($v, true), FILE_APPEND);

Where:

'/var/tmp/errors.log': Custom log file (This path is for Linux, we can specify other depending upon OS). print_r($v, TRUE) : logs $v (array/string/object) to log file. FILE_APPEND: Constant parameter specifying whether to append to the file if it exists, if file does not exist, new file will be created.