what is the use for error_log() in php?

Question

Also, tell me the difference between them.I know about empty() function(It will used to check whether the variable is empty or not).I wonder to know what's the main use for is_null() function.

Answer 1

The error_log() function sends an error to the server error log, a file or a remote destination.

This funtion returns TRUE on success, or FALSE on failure.

error_log(error,type,destination,headers)

Example:

<?php
// Send notification through the server log if we can not
// connect to the database.
if (!Ora_Logon($username, $password)) {
    error_log("Oracle database not available!", 0);
}

// Notify administrator by email if we run out of FOO
if (!($foo = allocate_new_foo())) {
    error_log("Big trouble, we're all out of FOOs!", 1,
               "operator@example.com");
}

// another way to call error_log():
error_log("You messed up!", 3, "/var/tmp/my-errors.log");
?>