# RLog Components

An RLog Component is typically a group of files with some shared purpose.

When programs are built with RLog, the value of RLOG_COMPONENT is used as the component name. If RLOG_COMPONENT is not set at compile time, you may receive a compiler warning, and the component will be set to "[unknown]".

For example when rlog is built, it specifies -DRLOG_COMPONENT="rlog".

For more detail on how to use components in subscriptions, see RLog Channels.