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PR_IntervalNow
==============
Returns the value of NSPR's free-running interval timer.
Syntax
------
.. code::
#include <prinrval.h>
PRIntervalTime PR_IntervalNow(void);
Returns
~~~~~~~
A :ref:`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:
.. code::
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);
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