From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Monjalon Subject: Re: [PATCH] mk: toolchain: gcc: query the compiler macros to obtain the gcc version Date: Wed, 23 Mar 2016 10:49:27 +0100 Message-ID: <10969139.eXE434OmqC@xps13> References: <1458666816-29778-1-git-send-email-mchandras@suse.de> <2653966.ML0Fr8PsdQ@xps13> <56F1CC20.50707@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Cc: dev@dpdk.org To: Markos Chandras Return-path: Received: from mail-wm0-f43.google.com (mail-wm0-f43.google.com [74.125.82.43]) by dpdk.org (Postfix) with ESMTP id 5ED05214A for ; Wed, 23 Mar 2016 10:51:09 +0100 (CET) Received: by mail-wm0-f43.google.com with SMTP id l68so15994661wml.1 for ; Wed, 23 Mar 2016 02:51:09 -0700 (PDT) In-Reply-To: <56F1CC20.50707@suse.de> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 2016-03-22 22:50, Markos Chandras: > On 22/03/16 22:34, Thomas Monjalon wrote: > > 2016-03-22 17:13, Markos Chandras: > >> This is similar to what's being used in the Linux kernel. Querying the > >> GCC macros directly gives more accurate results compared to -dumpversion > >> which could vary across distributions. > >> > >> Signed-off-by: Markos Chandras > >> --- > >> In openSUSE Tumbleweed (and in any other SUSE distribution which > >> uses (or will use) gcc >= 5), gcc -dumpversion returns '5'. This is on > >> purpose as discussed in https://bugzilla.opensuse.org/show_bug.cgi?id=941428 > > > > Good to know. It could be in the commit log. > > I can add this information to the commit message and send a v2 if needed. I will apply with this info. > >> -GCC_VERSION = $(subst .,,$(shell $(CC) -dumpversion | cut -f1-2 -d.)) > >> +GCC_MAJOR = $(shell echo __GNUC__ | $(CC) -E -x c - | tail -n 1) > >> +GCC_MINOR = $(shell echo __GNUC_MINOR__ | $(CC) -E -x c - | tail -n 1) > >> +GCC_VERSION = $(GCC_MAJOR)$(GCC_MINOR) > > > > Are we sure the minor will always be only one digit? > > Well, I can't be sure but minor has always been a single digit since gcc > >= 3 if I am not mistaken. But does it matter? What if it is two or more > digits? The previous code did something similar so if you had gcc > 5.12.34 installed (and lets assume this is what is being returned by > -dumpversion), it would have returned 512. The comparison would still > work as it is at the moment no? Yes, I was asking for an improvement in case it could happen. But GCC is probably conservative with numbering so we can keep only one digit.