Re: [Qemu-devel] [PATCH v3] build-sys: add --disable-vhost-user

[Thomas Huth <thuth@redhat.com>]

On 08.08.2017 14:37, Marc-André Lureau wrote:
> Hi
> 
> On Sun, Aug 6, 2017 at 11:19 PM Paolo Bonzini <pbonzini@redhat.com
> <mailto:pbonzini@redhat.com>> wrote:
> 
>     On 05/08/2017 09:39, Thomas Huth wrote:
>     >> +CONFIG_VHOST_USER_SCSI=$(and $(CONFIG_VHOST_USER),$(CONFIG_LINUX))
>     > I have to say that I don't really like using $(and ...) in our
>     makefiles
>     > like this. You rely on the fact that the config variables are
>     either set
>     > to "y" or not set at all ... but if somebody ever tries to set
>     > CONFIG_VHOST_USER=n and CONFIG_LINUX=y for example (which sounds
>     valid,
>     > too), this will break. Isn't there a better way of checking that both
>     > variables are set to "y" ?
> 
>     $(call land, ...) does exactly this.
> 
>  
> The patch is now merged. Thomas, Paolo, do you want to send a follow-up
> patch? If not, I can.

There are also a bunch of other spots in our Makefiles that use $(and
...) and shoult be converted to $(call land) instead. I already put a
TODO item on my list, so I'll eventually send a patch for this. But if
you're faster, feel free to post it first (just put me on CC: so that I
am aware of it).

 Thomas