From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Too many warnings building Emacs with GCC 6 on MSYS2-MinGW64 Date: Thu, 01 Sep 2016 19:04:45 +0300 Message-ID: <83a8frfvxe.fsf@gnu.org> References: <50083875-fbf6-d6b2-ffac-08c17c2bc696@alice.it> <83r395ko7o.fsf@gnu.org> <83h9a1kks6.fsf@gnu.org> <8337lklqrl.fsf@gnu.org> <11ac6b41-3a59-ec19-c414-151c08a91ba3@alice.it> <83oa48fiqn.fsf@gnu.org> <0749368a-c043-ef4b-8722-d5071f17a1e3@alice.it> <83h99zg0w0.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1472746103 28516 195.159.176.226 (1 Sep 2016 16:08:23 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Thu, 1 Sep 2016 16:08:23 +0000 (UTC) Cc: kbrown@cornell.edu, emacs-devel@gnu.org To: Angelo Graziosi Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Sep 01 18:08:16 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1bfUXD-00067Z-JC for ged-emacs-devel@m.gmane.org; Thu, 01 Sep 2016 18:08:11 +0200 Original-Received: from localhost ([::1]:37891 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfUXB-0005Xb-91 for ged-emacs-devel@m.gmane.org; Thu, 01 Sep 2016 12:08:09 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:44506) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfUTz-0003eG-Q3 for emacs-devel@gnu.org; Thu, 01 Sep 2016 12:04:56 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bfUTu-0006oX-Hh for emacs-devel@gnu.org; Thu, 01 Sep 2016 12:04:50 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:34543) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bfUTu-0006oS-E2; Thu, 01 Sep 2016 12:04:46 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:1176 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1bfUTt-0004o7-8x; Thu, 01 Sep 2016 12:04:46 -0400 In-reply-to: (message from Angelo Graziosi on Thu, 1 Sep 2016 17:42:06 +0200) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:207072 Archived-At: > Cc: kbrown@cornell.edu, emacs-devel@gnu.org > From: Angelo Graziosi > Date: Thu, 1 Sep 2016 17:42:06 +0200 > > > The prototype that fixes this, with 'int' as the return value, is > > wrong, and is IMO a MinGW64 GCC bug which should be reported. > > intptr_t is a 64-bit type in MinGW64, while int is still 32 bits. By > > enforcing the wrong type, GCC contradicts MinGW64's own library > > headers. > > I tested the test case (that using intptr_t) on OSX with gcc-6.1 and it > prints the same warning only using 'int' as return type the warning goes > away... On Unix, execve indeed returns an int, because it's a process ID. On Windows, the return value can be a process handle, which is a 64-bit data type on 64-bit Windows. That is why the return value must be intptr_t, not an int. The bug in MinGW64 GCC is that it uses the Unix model for the builtin execve, whereas it should have used the Windows model. Anyway, if you don't believe me, look on MSDN: https://msdn.microsoft.com/en-us/library/hyw61wtd.aspx