From mboxrd@z Thu Jan 1 00:00:00 1970 From: Danny Milosavljevic Subject: Re: Isnan Date: Sun, 31 Jul 2016 12:44:27 +0200 Message-ID: <20160731124427.09d60bc3@scratchpost.org> References: <20160731103520.GA9970@solar> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:33627) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bToEX-0007da-9S for guix-devel@gnu.org; Sun, 31 Jul 2016 06:44:38 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bToES-0007B3-Db for guix-devel@gnu.org; Sun, 31 Jul 2016 06:44:37 -0400 Received: from dd1012.kasserver.com ([85.13.128.8]:47838) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bToES-0007Az-7B for guix-devel@gnu.org; Sun, 31 Jul 2016 06:44:32 -0400 In-Reply-To: <20160731103520.GA9970@solar> List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+gcggd-guix-devel=m.gmane.org@gnu.org Sender: "Guix-devel" To: Andreas Enge Cc: guix-devel@gnu.org > Apparently the "std::" is missing in front of "isnan"; should this not be implicit? No. Many people in the C++ community frowns upon even doing "using namespace std" at all, never mind implicitly. http://stackoverflow.com/questions/1265039/using-std-namespace If you include math.h , isnan is called ::isnan . If you include cmath , isnan is called std::isnan . Also, std::isnan was added with C++11, so it's a new feature. Are you compiling with a C++11 compiler? What are the compiler flags used?