Locks

This chapter describes the NSPR API for creation and manipulation of a mutex of type PRLock.

• Lock Type
• Lock Functions

In NSPR, a mutex of type PRLock controls locking, and associated condition variables communicate changes in state among threads. When a programmer associates a mutex with an arbitrary collection of data, the mutex provides a protective monitor around the data.

In general, a monitor is a conceptual entity composed of a mutex, one or more condition variables, and the monitored data. Monitors in this generic sense should not be confused with monitors used in Java programming. In addition to PRLock, NSPR provides another mutex type, PRMonitor, which is reentrant and can have only one associated condition variable. PRMonitor is intended for use with Java and reflects the Java approach to thread synchronization.

For an introduction to NSPR thread synchronization, including locks and condition variables, see Introduction to NSPR.

For reference information on NSPR condition variables, see Condition Variables.

Lock Type

• PRLock

Lock Functions

• PR_NewLock creates a new lock object.
• PR_DestroyLock destroys a specified lock object.
• PR_Lock locks a specified lock object.
• PR_Unlock unlocks a specified lock object.