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Re: Timing an activity

on 7/27/04 3:43 PM, George Warner at email@hidden wrote:

> On Mon, 26 Jul 2004 20:18:38 -0600, Everett Sanmann
> <email@hidden> wrote:
>> I am attempting to implement a timer to record the time elapsed while an
>> activity ( such as recording a track from a vinyl record) is proceeding. I
>> found the following code snippet-posted by an Apple engineer-which I thought
>> would be applicable:
>
> Looks like my code.
>
>> [BEGIN]
>>
>> AbsoluteTime start = UpTime();
>>
>> // stuff to be timed
>> .
>> .
>> .
>>
>> AbsoluteTime stop = UpTime();
>>
>> AbsoluteTime delta = stop - start;
>>
>> double seconds = AbsoluteToNanoSeconds(delta) * 0.000000001f;
>>
>> [END]
>>
>> However, I found that "AbsoluteToNanoSeconds"-rather than returning a
>> double, returns a UnsignedWide struct, consisting of UInt32 hi and UInt32
>> lo. (Also, since Absolute time is the same struct, the compiler complains
>> that stop and start and not valid variables) -(I did attempt to read the
>> headers).
>
> It's actually returning a 64-bit value. You can use the UnsignedWideToUInt64
> macro to map between UnsignedWide's and UInt64's (they're in <Math64.h>).
>
> double seconds = UnsignedWideToUInt64 (AbsoluteToNanoSeconds(delta)) *
> 0.000000001f;
>
>> In my abysmal ignorance, I do not know how to convert this struct into a
>> number which I can use.
>> Am I completely on the wrong track?
>
> Nope.
Got it!
Thanks.
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References: 
 >re: Timing an activity (From: George Warner <email@hidden>)



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