From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35208) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1deSwu-00071v-6O for qemu-devel@nongnu.org; Sun, 06 Aug 2017 17:19:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1deSwp-0005k4-8p for qemu-devel@nongnu.org; Sun, 06 Aug 2017 17:19:00 -0400 Received: from mail-wm0-f44.google.com ([74.125.82.44]:38058) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1deSwp-0005jT-27 for qemu-devel@nongnu.org; Sun, 06 Aug 2017 17:18:55 -0400 Received: by mail-wm0-f44.google.com with SMTP id m85so54999661wma.1 for ; Sun, 06 Aug 2017 14:18:52 -0700 (PDT) References: <20170803090746.30532-1-marcandre.lureau@redhat.com> <1eca7ede-f103-ee90-1f9a-0fc44ef2b708@redhat.com> From: Paolo Bonzini Message-ID: Date: Sun, 6 Aug 2017 23:18:46 +0200 MIME-Version: 1.0 In-Reply-To: <1eca7ede-f103-ee90-1f9a-0fc44ef2b708@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3] build-sys: add --disable-vhost-user List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Huth , =?UTF-8?Q?Marc-Andr=c3=a9_Lureau?= , qemu-devel@nongnu.org Cc: Christian Borntraeger , cohuck@redhat.com, philippe.mathieu.daude@gmail.com, Alexander Graf , mst@redhat.com 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. Paolo