The error message that should be logged.


Says where the error should go. The possible message types are as follows:

error_log() log types
0 message is sent to PHP’s system logger, using the Operating System’s system logging mechanism or a file, depending on what the configuration directive is set to. This is the default option.
1 message is sent by email to the address in the destination parameter. This is the only message type where the fourth parameter, extra_headers is used.
2 No longer an option.
3 message is appended to the file destination. A newline is not automatically added to the end of the message string.
4 message is sent directly to the SAPI logging handler.

The destination. Its meaning depends on the message_type parameter as described above.