PR_CWait

Wait for a notification that a monitor's state has changed.

Syntax

#include <prcmon.h> 
PRStatus PR_CWait(
   void *address, 
   PRIntervalTime timeout);

Parameters

The function has the following parameters:

address

The address of the protected object--the same address previously passed to PR_CEnterMonitor.

timeout

The amount of time (in PRIntervalTime units) that the thread is willing to wait for an explicit notification before being rescheduled. If you specify PR_INTERVAL_NO_TIMEOUT, the function returns if and only if the object is notified.

Returns

The function returns one of the following values:

• PR_SUCCESS indicates either that the monitored object has been notified or that the interval specified in the timeout parameter has been exceeded.
• PR_FAILURE indicates either that the monitor could not be located in the cache or that the monitor was located and the calling thread was not the thread that held the monitor's mutex.

Description

Using the value specified in the address parameter to find a monitor in the monitor cache, PR_CWait waits for a notification that the monitor's state has changed. While the thread is waiting, it exits the monitor (just as if it had called PR_CExitMonitor as many times as it had called PR_CEnterMonitor). When the wait has finished, the thread regains control of the monitor's lock with the same entry count as before the wait began.

The thread waiting on the monitor resumes execution when the monitor is notified (assuming the thread is the next in line to receive the notify) or when the interval specified in the timeout parameter has been exceeded. When the thread resumes execution, it is the caller's responsibility to test the state of the monitored data to determine the appropriate action.