Re: [Qemu-devel] [Qemu-discuss] qemu-io-cmds does not compile on macOS

Re: [Qemu-devel] [Qemu-discuss] qemu-io-cmds does not compile on macOS

[Peter Maydell]

On Sun, 23 Jun 2019 at 16:22, Juan Rafael García Blanco
<juanrgar@gmail.com> wrote:
> I think the latest changes to qemu-io-cmds.c make it impossible to compile under macOS. It now uses clock_gettime, which is not available in this OS. I’m using 10.9.5; I think this function is now included in 10.12.
>
> I would step up to try to prepare a patch that uses a replacement in case it is being compiled in a macOS version that does not include that function. But I do not know if you want to support these ‘old' macOS versions…

Hi; thanks for this report. (This kind of bug report is better sent
to qemu-devel or to the launchpad bug tracker -- qemu-discuss
is mostly user-to-user conversations, and developers tend to
be on -devel; I've cc'd -devel on this.)

Our official support policy is that we support building with the
two most recent versions of macOS; in practice we might support
building with some earlier versions; as of commit 5588840ff77800e839
we definitely dropped support for anything earlier than 10.10.
So in theory we don't strongly care about anything before 10.13
at the moment; but if it's easy to avoid the problem it might be
worth doing that.

Alex, it looks like the relevant commit was one of yours.
Could you have a look at how easy it would be to support
systems without clock_gettime/CLOCK_MONOTONIC ?
I notice that other places in QEMU have #ifdeffery for
a lack of CLOCK_MONOTONIC, so we should ideally be
consistent, and either support systems without it, or else
say we require it and remove the remaining legacy ifdefs...

thanks
-- PMM

Re: [Qemu-devel] [Qemu-discuss] qemu-io-cmds does not compile on macOS

[Alex Bennée]

Peter Maydell <peter.maydell@linaro.org> writes:

> On Sun, 23 Jun 2019 at 16:22, Juan Rafael García Blanco
> <juanrgar@gmail.com> wrote:
>> I think the latest changes to qemu-io-cmds.c make it impossible to compile under macOS. It now uses clock_gettime, which is not available in this OS. I’m using 10.9.5; I think this function is now included in 10.12.
>>
>> I would step up to try to prepare a patch that uses a replacement in case it is being compiled in a macOS version that does not include that function. But I do not know if you want to support these ‘old' macOS versions…
>
> Hi; thanks for this report. (This kind of bug report is better sent
> to qemu-devel or to the launchpad bug tracker -- qemu-discuss
> is mostly user-to-user conversations, and developers tend to
> be on -devel; I've cc'd -devel on this.)
>
> Our official support policy is that we support building with the
> two most recent versions of macOS; in practice we might support
> building with some earlier versions; as of commit 5588840ff77800e839
> we definitely dropped support for anything earlier than 10.10.
> So in theory we don't strongly care about anything before 10.13
> at the moment; but if it's easy to avoid the problem it might be
> worth doing that.
>
> Alex, it looks like the relevant commit was one of yours.

Which commit was that?

> Could you have a look at how easy it would be to support
> systems without clock_gettime/CLOCK_MONOTONIC ?
> I notice that other places in QEMU have #ifdeffery for
> a lack of CLOCK_MONOTONIC, so we should ideally be
> consistent, and either support systems without it, or else
> say we require it and remove the remaining legacy ifdefs...

Ahh was this the changes to qemu-iocmds to use proper monotonic clocks
to avoid /0 that was occuring with gettimeofday?

In the main code we have comments about:

        /* XXX: using gettimeofday leads to problems if the date
           changes, so it should be avoided. */

Is this the only option for old MacOS?

>
> thanks
> -- PMM


--
Alex Bennée