Clock() question

[Tadeusz Jordan]

Hello,

Could anyone tell me what are the units of the value returned by the
function clock()? I thought they are CLOCKS_PER_SECs of a second but my
prof. crossed them out on my report.

Thanks for any help.

Tadeusz

 

[Lionel B]

Hello,

Could anyone tell me what are the units of the value returned by the
function clock()? I thought they are CLOCKS_PER_SECs of a second but my
prof. crossed them out on my report.

Might your prof. have been looking for the answer 1/CLOCKS_PER_SEC ... ?

 

[Lionel B]

Might your prof. have been looking for the answer 1/CLOCKS_PER_SEC ... ?

Make that 1/CLOCKS_PER_SEC *seconds*. Apparently POSIX requires that
CLOCKS_PER_SEC = 1000000, so I guess "seconds/1000000" might be an
acceptable answer.

 

[Juha Nieminen]

Could anyone tell me what are the units of the value returned by the
function clock()? I thought they are CLOCKS_PER_SECs of a second but my
prof. crossed them out on my report.

My guess is that your professor didn't know the language standard
well enough to know that clock() and CLOCKS_PER_SEC are indeed standard
(well, according to its linux manpage they are).

 

[James Kanze]

Make that 1/CLOCKS_PER_SEC *seconds*. Apparently POSIX requires that
CLOCKS_PER_SEC = 1000000, so I guess "seconds/1000000" might be an
acceptable answer.

Only if the subject matter was modern Unix, and not C or C++.
(On many of the older compilers I've used, the value was
typically 50 or 60, depending on whether the machine was in
Europe or the US.)

 

[Lionel B]

Only if the subject matter was modern Unix, and not C or C++.

Um, what about C or C++ on a POSIX system? AFAIK clock() is standard C
(and C++) while CLOCKS_PER_SEC = 1000000 is mandatory on a POSIX stystem.
This is why I said "*might* be an acceptable answer" (sorry if that
wasn't clear).

 

[Lionel B]

My guess is that your professor didn't know the language standard
well enough to know that clock() and CLOCKS_PER_SEC are indeed standard
(well, according to its linux manpage they are).

CLOCKS_PER_SEC may indeed be standard but it is not the units of the
value returned by the clock(). "1/CLOCKS_PER_SEC seconds" is.

 

[Tadeusz Jordan]

CLOCKS_PER_SEC may indeed be standard but it is not the units of the
value returned by the clock(). "1/CLOCKS_PER_SEC seconds" is.

"1/CLOCKS_PER_SEC seconds" is that an equivalent statement to
"CLOCKS_PER_SECs of a second" ?

Tadeusz

 

[Lionel B]

Please don't quote sigs

"1/CLOCKS_PER_SEC seconds" is that an equivalent statement to
"CLOCKS_PER_SECs of a second" ?

Not quite: "CLOCKS_PER_SEC-ths of a second" Try this for eg.
CLOCKS_PER_SEC = 1000