To add some context to Keith's very correct reply: SQLite uses these internally and already does a pretty amazing job of controlling multi-threaded access if you let it. You are allowed to create mutexes, gain access to those used by SQLite or use them for your own purposes, so these calls are exposed, but they are not required for you to call them for SQLite to operate normally. If you are asking out of interest of how sqlite itself uses them to control multi-threaded access - Nobody typically does this, so I suppose the best examples are where they are used in the SQLite code itself. (Which you can download and browse freely). Hope that helps!