Date: Tue, 5 Dec 2000 13:43:22 -0800 From: "Jonathan Graehl" <jonathan@graehl.org> To: <freebsd-hackers@freebsd.org> Subject: POSIX clock_gettime, clock_getres return errno invalid argument for CLOCK_PROF and CLOCK_VIRTUAL Message-ID: <NCBBLOALCKKINBNNEDDLOELLDHAA.jonathan@graehl.org>
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The resolution (clock_getres) of CLOCK_REALTIME is 783 ns on my
4.2-STABLE/Pentium 2. Is there a more accurate timer available?
(clearly, gettimeofday is limited to 1000ns resolution ;)
(submitted pr follows)
While there is no problem with CLOCK_REALTIME, POSIX clock_gettime,
clock_getres return errno invalid argument for CLOCK_PROF and
CLOCK_VIRTUAL, which are documented in the man pages (section 2) as
being user+system and user time, respectively.
FreeBSD 3jane 4.2-STABLE FreeBSD 4.2-STABLE #0: Sat Dec 2 14:46:10 PST
2000 root@3jane:/ext/obj/usr/src/sys/NEWJANE i386
/* demonstrates that the clock_get... calls succed for CLOCK_REALTIME
but fail for CLOCK_PROF and CLOCK_VIRTUAL */
#include <sys/time.h>
#include <stdio.h>
int main() {
struct timespec t;
puts("CLOCK_PROF");
if (clock_gettime(CLOCK_PROF, &t))
perror(NULL);
if (clock_getres(CLOCK_PROF, &t))
perror(NULL);
puts("\nCLOCK_VIRTUAL");
if (clock_gettime(CLOCK_VIRTUAL, &t))
perror(NULL);
if (clock_getres(CLOCK_VIRTUAL, &t))
perror(NULL);
puts("\nCLOCK_REALTIME");
if (clock_gettime(CLOCK_REALTIME, &t))
perror(NULL);
if (clock_getres(CLOCK_REALTIME, &t))
perror(NULL);
}
Immediate fix: remove mention of CLOCK_VIRTUAL AND CLOCK_PROF from
sys/time.h and man 2 clock_gettime
Real fix: implement the documented POSIX functionality
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