How thread safe is EnableWriteAheadLogging in the context of real usage and SQLite documentation?

The android documentation describes "EnableWriteAheadLogging" over here:

http://ift.tt/1GFJoRy

"This method enables parallel execution of queries from multiple threads on the same database"

However, according to the SQLite documentation: http://ift.tt/1dkDSrz

there are two kinds of multithreading for SQLite: "Serialized" and "Mulit-thread". Which one is used when using "EnableWriteAheadLogging"?

In addition, if my database needs to be accessed by both my app and a background service, does it help to use EnableWriteAheadLogging? Which actions should I take to make sure this can be done in a thread safe way?