Date: Fri, 13 Oct 1995 14:57:26 +0400
From: "Alexander V. Lukyanov" <lav AT yars DOT free DOT net>
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Re: clock() unit ?

>From: nicolas AT jupiter DOT ceng DOT cea DOT fr (Eric NICOLAS)
>Subject: clock() unit ?

>Could someone tell in what unit is the result of clock() function ??

>ANSI C tell that there should be a CLK_TCK constant which says that, but I found
>somewhere in djgpp .H a #define CLK_TCK 100, and when trying that it is obvious
>that this is wrong.

>In fact, it seems that there are about 1 million clock() units per seconds. But
>what is the real value ?

>This is an important point in order to preserve compatibility between djgpp programs
>and TurboC programs. I think there SHOULD be a CLK_TCK constant with the right value
>in the standard .H.


This is a conflict between standards ANSI C and POSIX.1

In POSIX, clock() returns clock_t type, which should be divided by result
of sysconf(_SC_CLK_TCK) to get seconds. CLK_TCK declared obsolete.

In ANSI C clock() returns clock_t too, but it should be divided
by CLOCKS_PER_SEC.