Introductory Blog Post.

Logging facilities categorize logged Error messages. They correspond to directories in the data/log/ directory. Plugins may use their own facilities.

DokuWiki defines three logging facilities by default:

• error – anything that should not happen and is the result of a problem with the code, environment, configuration or user interaction.
• deprecated – logs the use of deprecated code. The stack trace should help identifying the code that needs to be updated
• debug – messages that help during development or configuration but are usually not needed

Which facilities actually should be logged can be configured through the dontlog option.

if you only need to write errors only, without deprecated, and debug, then the line in file

conf/dokuwiki.php

must look like this

$conf['dontlog'] = 'deprecated,debug';

DokuWiki registers error handlers that will automatically try to catch all run-away exception, errors and fatals. It will display an informatory message to the end user and log the error to the error facility.