libtorrent fails to compile using clang with libc++ about libtorrent

[rakshasa]

Considering I've recently upgraded this should get fixed soon.

ATM use the macports clang to compile.

[rakshasa]

BTW, I'm pretty sure the union above was added since it is supposed to be supported by C++11.

Need to look into the copy constructor part.

[mistydemeo]

ATM use the macports clang to compile.

The system clang also works in libstdc++ mode, this is specifically a libc++ issue. If Macports's clang works, I imagine it's because it's defaulting to libstdc++.

[ahaghgoo]

So if I upgraded to Mavericks and installed rtorrent via MacPorts, would libtorrent "build" (I'm a layman to the world of developers)?

[clarkewd]

so just to check - there is still no way to build rtorrent on mavericks even though this commit says:

libtorrent: use libstdc++ if compiling with clang on mavericks, fixes

right? I can't get it to compile even after trying with that added line...

[mistydemeo]

@clarkewd Can you discuss Homebrew issues on the Homebrew tracker? The issue is Homebrew/legacy-homebrew#23483

[rakshasa]

CC=clang CXX=clang++ CXXFLAGS="-Wno-deprecated-declarations -O3 -std=c++11 -stdlib=libc++" ./configure

With these settings I could compile with C++11 check succeeding.

[Blub]

There are several issues there with clang 3.3. Here's what I use on ArchBSD to build it:
https://github.com/ArchBSD/abs/blob/master/community/libtorrent/PKGBUILD#L38
Starting from line 38:
The first two are missing headers - FreeBSD systems seem to have much stricter headers around.

The parts below are to make it actually compile as C++11 code.
libc++'s tr1 headers don't actually make a tr1 namespace.

Also, tr1 is not an actual standard, you shouldn't use it in an actual project.

(Note that I explicitly set -std=c++11 in the CXXFLAGS since the configure checks for it fail.)

And the patch used is to avoid link errors when building rtorrent:
https://github.com/ArchBSD/abs/blob/master/community/libtorrent/missing_references.diff

Declaring static const variables only in the class-def is simply not enough. I don't know why exactly clang wants to take a reference to them in the rtorrent code - it shouldn't - but in any case, providing the actual symbols is more correct.

[andyattebery]

I'm still unable to libtorrent using clang (not via homebrew). I set the CXXFLAGS to

CXXFLAGS="-Wno-deprecated-declarations -O3 -std=c++11 -stdlib=libc++"

as suggested above and received this error:

Making all in data
/bin/sh ../../../libtool  --tag=CXX   --mode=compile clang++ -DHAVE_CONFIG_H -I. -I../../.. -I. -I./.. -I./../.. -I../../..    -Wno-deprecated-declarations -O3 -std=c++11 -stdlib=libc++ -g -DDEBUG -fvisibility=hidden -D_THREAD_SAFE   -MT block.lo -MD -MP -MF .deps/block.Tpo -c -o block.lo block.cc
libtool: compile:  clang++ -DHAVE_CONFIG_H -I. -I../../.. -I. -I./.. -I./../.. -I../../.. -Wno-deprecated-declarations -O3 -std=c++11 -stdlib=libc++ -g -DDEBUG -fvisibility=hidden -D_THREAD_SAFE -MT block.lo -MD -MP -MF .deps/block.Tpo -c block.cc  -fno-common -DPIC -o .libs/block.o
In file included from block.cc:44:
In file included from ./../../protocol/peer_connection_base.h:42:
./../../torrent/poll.h:40:10: fatal error: 'tr1/functional' file not found
#include <tr1/functional>

Which points to the real issue that @Blub mentions above that libc++ doesn't include the namespace tr1 since the majority of its features are included in c++11. So would the best option moving forward be adding preprocessor checks for libc++ to remove referencing the tr1 namespace as suggested here: http://stackoverflow.com/questions/13219007/xcode-4-5-tr1-type-traits-file-not-found?

[Blub]

Your compile error is about the missing tr1/functional file in the include path, not the namespace for inside the code. If you have c++11 headers around you can try using those (just remove the tr1/ from the path) instead and then you'll get the namespace related errors. I wonder if the other issues still exist with clang 3.4+ as they seem weird to even be there to begin with. (I'll see once FreeBSD merges the next update into the stable/10 branch)

[dhruvit-r]

There is clang++ for compiling C++ tuff. Try that.

[Blub]

/me points to the clang++ part of the commands pasted above...

[andyattebery]

@Blub Yea, I realize its that stdc++ doesn't have the "tr1" headers inside of a "tr1" directory. This is the correct behavior for c++11, right? So I've tried removing all references to tr1 in the code and recompiling via clang++ and manually setting -std=c++11 in the CXXFLAGS since the configure script fails for that check as @rakshasa mentions above. I'm still debugging compile errors for std::bind (instead of std::tr1::bind). However, once this is working, this should be how the code should be structured — without explicit references to tr1 — right?

[Blub]

It should. As you can see in the PKGBUILD link I posted above, there are a few more replacements happening. (like .assign -> .fill - basically everything after the port-patches are applied is to compile as c++11 as we prefer clang/libc++-compiled packages on ArchBSD)
I haven't tried it against a current git clone though, only against the version tarball referenced in the PKGBUILD.

[arp242]

This is also an issue with FreeBSD, where GCC was removed entirely in favour of Clang.

Someone seems to have created a patch, though:
http://www.freebsd.org/cgi/query-pr.cgi?pr=ports/185299

(I'm not the author of this patch, and I didn't test it).

[rakshasa]

I have started work on a C++11 branch, however it is not yet ready.

https://github.com/rakshasa/libtorrent/tree/c++11

[rakshasa]

Both libtorrent and rtorrent now have c++11 branches, which should work with clang.

[mistydemeo]

Thank you, I'll test! Is this expected to make it into a future release?

[rakshasa]

The next release, most likely this week or next, will become the stable branch.

The unstable branch will require C++11, mainly because I want to play with the new features and 3 years is enough for the distros to catch up.

[rakshasa]

Merged C++11 branch.

[bapzangbo]

I have error when build with xcode6 libtorrent-rasterbar.a

Undefined symbols for architecture i386:
"libtorrent::absolutetime_deprecated_()", referenced from:
libtorrent::session::session(libtorrent::fingerprint const&, int, unsigned int) in main.o
"libtorrent::session::init(std::__1::pair<int, int>, char const*, libtorrent::fingerprint const&, unsigned int)", referenced from:
libtorrent::session::session(libtorrent::fingerprint const&, int, unsigned int) in main.o
"libtorrent::session::start(int)", referenced from:
libtorrent::session::session(libtorrent::fingerprint const&, int, unsigned int) in main.o
"libtorrent::session::~session()", referenced from:
_main in main.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)