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: libnettle/libhogweed WIP Date: Mon, 17 Apr 2017 20:11:32 +0300 Message-ID: <831ssrdkmz.fsf@gnu.org> References: <83a89gq3us.fsf@gnu.org> <87bmtjiv0w.fsf_-_@lifelogs.com> <83o9xjn06c.fsf@gnu.org> <87shmeb5ln.fsf_-_@lifelogs.com> <83y3w5z1ez.fsf@gnu.org> <87lgr6yakj.fsf@lifelogs.com> <87wpamww9k.fsf@lifelogs.com> <8337daggnj.fsf@gnu.org> <87d1cdwxt6.fsf@lifelogs.com> <83tw5pg1q3.fsf@gnu.org> <87zifhulc2.fsf@lifelogs.com> <83h91og80k.fsf@gnu.org> <87pogbuhoe.fsf@lifelogs.com> <834lxndmd9.fsf@gnu.org> <87efwrug6z.fsf@lifelogs.com> Reply-To: Eli Zaretskii NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1492449101 22840 195.159.176.226 (17 Apr 2017 17:11:41 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Mon, 17 Apr 2017 17:11:41 +0000 (UTC) To: emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Mon Apr 17 19:11:33 2017 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 1d0ABY-0005kr-Qp for ged-emacs-devel@m.gmane.org; Mon, 17 Apr 2017 19:11:32 +0200 Original-Received: from localhost ([::1]:37968 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d0ABe-0006S7-QI for ged-emacs-devel@m.gmane.org; Mon, 17 Apr 2017 13:11:38 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:36362) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d0AB6-0006S2-48 for emacs-devel@gnu.org; Mon, 17 Apr 2017 13:11:05 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d0AB2-0000ac-Ts for emacs-devel@gnu.org; Mon, 17 Apr 2017 13:11:04 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:48231) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d0AB2-0000aQ-Pr for emacs-devel@gnu.org; Mon, 17 Apr 2017 13:11:00 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:1809 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1d0AB2-0007l8-6H for emacs-devel@gnu.org; Mon, 17 Apr 2017 13:11:00 -0400 In-reply-to: <87efwrug6z.fsf@lifelogs.com> (message from Ted Zlatanov on Mon, 17 Apr 2017 12:55:32 -0400) 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:214081 Archived-At: > From: Ted Zlatanov > Date: Mon, 17 Apr 2017 12:55:32 -0400 > > EZ> Why not use my suggestion, producing a Lisp string out of C string > EZ> just before returning? > > I don't see the difference between allocating a C string + > make_unibyte_string(), and doing > > Lisp_Object storage = make_uninit_string (storage_length); > ... > return make_unibyte_string (SSDATA (storage), storage_length); It's a minor issue, admittedly. make_unibyte_string allocates a Lisp string, which does more than just allocate the string data (e.g., Lisp memory allocation is non-reentrant, so it calls block_input). It also requires allocation whose alignment is potentially more stringent than simple C memory allocation, certainly so if SAFE_ALLOCA decides to use alloca, not malloc, so it slightly increases memory pressure. IOW, it's a kind of aesthetic issue: code that allocates a Lisp string just so it could use its data as storage, and then actually makes a different string to return to the caller, looks less elegant to me. > because either way the data has to be copied, and the latter needs less > care with freeing the memory. Using SAFE_ALLOCA is not complicated, either. > It's really not a big deal to switch to your suggestion, I just > don't know why it matters? I hope the above explains why.