Hi Henrik,
On 13.08.2010 23:14, commits@squeakvm.org wrote:To be finicky, it's not actually undocumented though, if I interpreted the man pages correctly :)Author: eliot Date: 2010-08-13 14:14:21 -0700 (Fri, 13 Aug 2010) New Revision: 2253 Modified: branches/Cog/platforms/unix/vm/sqUnixHeartbeat.c Log: Integrate Henrik Johansen's fix for the nanosleep call in the heartbeat. Modified: branches/Cog/platforms/unix/vm/sqUnixHeartbeat.c =================================================================== --- branches/Cog/platforms/unix/vm/sqUnixHeartbeat.c 2010-08-11 18:03:02 UTC (rev 2252) +++ branches/Cog/platforms/unix/vm/sqUnixHeartbeat.c 2010-08-13 21:14:21 UTC (rev 2253) @@ -607,6 +607,8 @@ struct timespec naptime = beatperiod; while (nanosleep(&naptime, &naptime) == -1 + /* oversleeps can return tv_sec = -1 tv_nsec approx 999999999 */ + && naptime.tv_sec >= 0 /* avoid undoc'ed oversleep behaviour */ && (naptime.tv_sec > 0 || naptime.tv_nsec > MINSLEEPNS)) /*repeat*/ if (errno != EINTR) { perror("nanosleep");
http://www.opengroup.org/onlinepubs/009695399/functions/nanosleep.html
http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man2/nanosleep.2.html
"If the rmtp argument is non-NULL, thetimespec structure referenced by it is updated to contain the amount of time remaining in the interval (the requested time minus the time actually slept). "
Since it also specifies that the valid range for tv_nsec is 0 - 999999999, a negative value for tv_sec is the only valid option when it has overslept before being interrupted.
Cheers,
Henry