From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/13631 Path: news.gmane.org!.POSTED!not-for-mail From: Michele Portolan Newsgroups: gmane.linux.lib.musl.general Subject: Re: New to musl and C++ compiling Date: Mon, 21 Jan 2019 14:13:07 +0100 Message-ID: References: <20190121115313.GR21289@port70.net> <20190121120224.GS21289@port70.net> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: ciao.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: ciao.gmane.org 1548076394 30215 195.159.176.228 (21 Jan 2019 13:13:14 GMT) X-Complaints-To: usenet@ciao.gmane.org NNTP-Posting-Date: Mon, 21 Jan 2019 13:13:14 +0000 (UTC) User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 To: musl@lists.openwall.com Original-X-From: musl-return-13647-gllmg-musl=m.gmane.org@lists.openwall.com Mon Jan 21 14:13:12 2019 Return-path: Envelope-to: gllmg-musl@m.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by ciao.gmane.org with smtp (Exim 4.84_2) (envelope-from ) id 1glZO3-0007nZ-Jl for gllmg-musl@m.gmane.org; Mon, 21 Jan 2019 14:13:11 +0100 Original-Received: (qmail 18270 invoked by uid 550); 21 Jan 2019 13:13:19 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 18252 invoked from network); 21 Jan 2019 13:13:19 -0000 In-Reply-To: <20190121120224.GS21289@port70.net> Content-Language: en-US X-Greylist: Whitelist-UGA SMTP Authentifie (portolam@univ-grenoble-alpes.fr) via smtps-465 ACL (99) Xref: news.gmane.org gmane.linux.lib.musl.general:13631 Archived-At: Thanks for the information. You say "use a cross compiler that is built for musl" ... how do I do this? Binaries are useful, but if I can also get the build process right it is more powerful, and easier to pass to students (I am an academic). Thanks, Michele On 21/01/2019 13:02, Szabolcs Nagy wrote: > * Szabolcs Nagy [2019-01-21 12:53:13 +0100]: > >> * Michele Portolan [2019-01-21 11:24:12 +0100]: >>> Hello, >>> >>> I just installed MUSL because I have a C++ multithreaded application that >>> uses threads heavily and I would like to make it independent from an OS. I >>> was able to easily install and run MUSL for C targets, but when I try a >>> simple C++ Hello world I get an error for the standard libs. >>> >>> My file is the simplest possible (no multithreading to start with): >>> >>>  #include >>> >>>  int main() { >>>           std::cout << "Hello, World" << std::endl; >>>           return 0; >>> } >>> >>> Here is my output for standard and musl-based compilation. >>> >>> portolan@noumea:~/musl/examples$ g++ -o test_cpp test_cpp.cpp >>> portolan@noumea:~/musl/examples$ ./test_cpp >>> Hello, World >>> portolan@noumea:~/musl/examples$ g++ -o test_cpp test_cpp.cpp -specs >>> "/home/portolan/musl/install/lib/musl-gcc.specs" >> for c++ the recommended practice is to use a cross compiler that >> is built for musl, instead of a glibc based native compiler with >> a specs file or other wrapping mechanism, because c++ headers are >> difficult to get right: in this case the specs file disabled all >> c++ header paths, you need to add those back manually, see >> >> g++ -v -E -xc++ - > >> but there may be still issues >> - the header ordering matters as libstdc++ uses include_next and >> - some headers are installed based on the libc found at configure >> time of gcc, so the abi is slightly different depending on what >> libc you built your compiler for, >> - e.g. with static linking (which you need if you want a portable >> executable) one issue is that libstdc++ has a broken way to >> detect multi-threadedness and all locks become nops (unless your >> binary has a definition for the 'pthread_cancel' symbol). >> if gcc is configured for *-musl* this is fixed. >> >> in short: use a cross compiler targetting *-linux-musl, there are >> prebuilt ones at http://musl.cc/ >> (note that you will have to build and install all your application >> dependencies into a path where the cross compiler can find them) > oh and if you have many dependencies then the simplest way is of > course to use a musl based distro (alpine, void, adelie,..) then > you can use all the prebuilt packages and the native toolchain > with g++ -static and you get a portable executable. > (setting up a chroot or docker with whatever distro should not be > too much work). > >>> test_cpp.cpp:1:11: fatal error: iostream: No such file or directory >>>   #include >>>            ^~~~~~~~~~ >>> compilation terminated. >>> >>> I am probably missing something REALLY basic, at least I hope so! >>> >>> Best regards, >>> >>> >>> Michele