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Measuring Elapsed Time

Measurement of elapsed time is done by simply obtaining the time before and after the event to be timed. The difference of these two values indicates the elapsed time. Time, in this context, refers to a 64-bit AbsoluteTime count maintained by Mac OS. The count is set to 0 by the operating system during its initialization at system startup time. Conversion routines are provided in a shared library to convert from AbsoluteTime to 64-bit Nanoseconds or 32-bit Duration values.

© 1999 Apple Computer, Inc. – (Last Updated 26 March 99)