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From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: CLOCKS_PER_SEC
Date: Thu, 13 Oct 2016 11:29:17 -0700
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Lowell Gilbert <lgusenet@be-well.ilk.org> writes:
> Keith Thompson <kst-u@mib.org> writes:
>> BartC <bc@freeuk.com> writes:
>>> CLOCKS_PER_SEC determines how the result of the clock() function is 
>>> interpreted.
>>>
>>> But it seems to be defined as macro in time.h.
>>>
>>> Any ideas on how to determine that value when calling clock() as foreign 
>>> function from another language? I want to avoid OS-specific functions 
>>> unless they are available on both Windows and Linux.
>>>
>>> (At the moment, CLOCKS_PER_SEC seems to be usually 1000 on Windows and 
>>> 1000000 on Linux. I suppose I could detect abnormally large values of 
>>> clock() and infer it that way, but I think there will be some overlap in 
>>> the set of valid results.)
>>
>> Write a C function that returns the value of the macro, and call that
>> function from the foreign language.  Depending on your build system, you
>> can probably do this at configuration time rather than at run time.
>
> Or write a wrapper that returns the equivalent in nanoseconds.

Assuming that 1/CLOCKS_PER_SEC is a whole number of nanoseconds.
(I don't object to making the assumption, I'm just pointing out
that it is one.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"