Monotonic clocks

Chris Vine chris at
Mon May 24 13:38:01 UTC 2010

On Mon, 24 May 2010 14:05:13 +0100
Chris Vine <chris at> wrote:

> I am the upstream maintainer of efax-gtk and I am told recent versions
> of the program will not compile on the FreeBSD port of debian, because
> FreeBSD does not appear to provide pthread_condattr_setclock() to set
> a monotonic clock on condition variables.
> The program configuration script calls up sysconf() to determine
> whether the POSIX advanced realtime option (_SC_MONOTONIC_CLOCK) is
> provided, and FreeBSD's sysconf() indicates that it is.  Is anything
> else needed to enable monotonic clocks on BSD, or is sysconf()
> incorrectly advertising the implementation of monotonic clocks in
> BSD's libc?

Ah, on looking up the SUS it looks as if I have to check
_SC_CLOCK_SELECTION as well (although it appears rather pointless to
have a monotonic clock if you can't actually select it).


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