Are Google journal entries wrapped in a mutex?

Using the Google logging library (glog-0.3.2), are there individual entries sent to the log wrapped by the mutex? That is, can other recordings spoil the recording? Think it translates, verb-streams? And if the registrar is configured to echo to the console, as well as to the file without its own mutex, is there a way to block printf / cout from distorting output from LOG ()? I suspect not, but wondered if there could be a way to block a mutex that could wrap up a few statements.