PR_IntervalNow

Returns the value of NSPR’s free-running interval timer.

Syntax

#include <prinrval.h>

PRIntervalTime PR_IntervalNow(void);

Returns

A PRIntervalTime object.

Description

You can use the value returned by PR_IntervalNow() to establish epochs and to determine intervals (that is, compute the difference between two times). PR_IntervalNow() is both very efficient and nonblocking, so it is appropriate to use (for example) while holding a mutex.

The most common use for PR_IntervalNow() is to establish an epoch and test for the expiration of intervals. In this case, you typically call PR_IntervalNow() in a sequence that looks like this:

PRUint32 interval = ... ; // milliseconds
// ...
PRStatus rv;
PRIntervalTime epoch = PR_IntervalNow();
PR_Lock(data->mutex);
while (!EvaluateData(data))  /* wait until condition is met */
{
    PRUint32 delta = PR_IntervalToMilliseconds(PR_IntervalNow() - epoch);
    if (delta > interval) break;  /* timeout */
    rv = PR_Wait(data->condition, PR_MillisecondsToInterval(interval - delta));
    if (PR_FAILURE == rv) break;  /* likely an interrupt */
}
PR_Unlock(data->mutex);