- Boost - lists.boost.org

Re: [boost] [Boost.Move] [Boost.Container] Compiling with older versions of Boost and Performance
by Thomas Jordan 09 Jan '12

09 Jan '12

> Message: 3 > Date: Sat, 07 Jan 2012 15:58:20 +0100 > From: "Vicente J. Botet Escriba" <vicente.botet(a)wanadoo.fr> <snip> > Le 07/01/12 12:10, Thomas Jordan a ?crit : >> Hi, >> I am interested in experimenting with v1.48 Boost.Move and >> Boost.Container. However, I am otherwise constrained to using Boost >> libraries v1.33.1 with >> a Sun C++ v5.10 compiler. I couldn't seem any 'Boost library >> dependencies' listed in the Move/Container documentation, but a quick >> look through the header files suggests >> that it is mainly MPL and Type Traits. So... >> First question: would it be feasible for me to combine the headers for >> these two libraries with the v1.33.1 libraries and get it to work (albeit >> maybe with a little customisation), or would it be a big job/non-starter? >> Second question - I don't see any performance analysis published for >> Boost.Move. I know that move semantics is about more than improved >> performance, but am interested in that side of things, especially as the >> above compiler appears suboptimal in terms of copy elision and RVO. I am >> wondering for example whether are there any (compiler-specific) factors >> which could mitigate against the performance benefits of doing a move vs >> a copy of a vector, using these libraries, for example. >> > > Hi, > > unfortunately Boost.Move and Boost.Container are not working up to now > on Sun c++ even on trunk (1.49). See > http://www.boost.org/development/tests/trunk/developer/container.html. > > Best, > Vicente Thanks for pointing me to that. In general is there anything more detailed than pass/fail available to look at? Is the assumption that something with so many fails it not fixable one the library side, and is not worth investigating? Regards, T.

2 1

[docs][crc] Did I do new documentation correctly?
by Daryle Walker 08 Jan '12

08 Jan '12

I completely redid the documentation for Boost.CRC in changeset [76335]. It uses Doxygen and Quickbook. I guessed on how to do it by copying files from Boost.Move. But I only did stuff within the BOOST_ROOT/libs/crc/* directory. I didn't make changes to other directories, especially the BOOST_ROOT/doc/* directory. Is stuff in that directory supposed to be automatically built? Other concerns: 1. The quickbook/doxygen system doesn't seem to handle "\todo" constructs correctly. 2. Is there a way to #define various common macros, like BOOST_STATIC_CONSTANT, so they get expanded correctly in Doxygen? Is there a "Doxyfile," or can the needed Doxygen parameters be tweaked in the Jamfile.v2? 3. I guessed that the next release will be "1.49.0", is that right? 4. Content-wise, did I miss anything? Daryle W.

3 4

compile time parser generator
by Martin Bidlingmaier 08 Jan '12

08 Jan '12

Hello, with c++11's constexpr it got possible to parse strings in c++ at compile time. I've written a parser generator to create an AST for a given EBNF syntax at compile time, which can be traversed at both run time and compile time (actually, parsing can take place at run time, too, but it's probably rather slow). At the moment, the only compiler I know of that implements enough of c++11 features is gcc (version >= 4.6). Is refining my implementation worth the effort, has such a library a chance to make it into boost? Is maybe somebody already working on this? Sincerely, Martin Bidlingmaier -- NEU: FreePhone - 0ct/min Handyspartarif mit Geld-zurück-Garantie! Jetzt informieren: http://www.gmx.net/de/go/freephone

7 10

no match for ‘operator=’ error with circular_buffer iterator when addressing buffer by reference?
by Bernd Prager 08 Jan '12

08 Jan '12

I am trying do use a circular_buffer iterator and run into problems when I try to write a copy constructor for my class. g++ (GCC) 4.5.3 generates following error: Test.cpp: In copy constructor ‘Test::Test(const Test&)’: Test.cpp:23:18: error: no match for ‘operator=’ in ‘it2 = boost::circular_buffer<T, Alloc>::begin() const [with T = int, Alloc = std::allocator<int>, boost::circular_buffer<T, Alloc>::const_iterator = boost::cb_details::iterator<boost::circular_buffer<int>, boost::cb_details::const_traits<std::allocator<int> > >]()’ /usr/local/include/boost/circular_buffer/details.hpp:253:15: note: candidate is: boost::cb_details::iterator<Buff, Traits>& boost::cb_details::iterator<Buff, Traits>::operator=(const boost::cb_details::iterator<Buff, Traits>&) [with Buff = boost::circular_buffer<int>, Traits = boost::cb_details::nonconst_traits<std::allocator<int> >, boost::cb_details::iterator<Buff, Traits> = boost::cb_details::iterator<boost::circular_buffer<int>, boost::cb_details::nonconst_traits<std::allocator<int> > >] What do I miss. Can anybody help? Thank you, -- Bernd #include <boost/circular_buffer.hpp> class Test { public: Test(); Test(const Test&); private: boost::circular_buffer<int> b; }; Test::Test() { b.resize(10); } Test::Test(const Test &t) { b.resize(10); size_t s1 = b.size(); size_t s2 = t.b.size(); boost::circular_buffer<int>::iterator it1 = b.begin(); boost::circular_buffer<int>::iterator it2 = t.b.begin(); } int main() { Test *t = new Test(); return 0; }

2 2

Re: [boost] [Boost.smart_ptr] Thread Safety
by Thomas Jordan 08 Jan '12

08 Jan '12

Message: 7 Date: Sat, 07 Jan 2012 16:49:07 -0500 From: Dave Abrahams <dave(a)boostpro.com> To: boost(a)lists.boost.org Subject: Re: [boost] [Boost.smart_ptr] Thread Safety Message-ID: <m24nw7p4j0.fsf(a)pluto.luannocracy.com> Content-Type: text/plain >on Sat Jan 07 2012, "Thomas Jordan" <thomasjordan-AT-btinternet.com> wrote: >> Hi, >> Is shared_array completely thread-safe, including >> destruction/reference counting? From the code in >> /boost/detail/sp_counted_base_pt.hpp it looks like it probably is but >> according to >> >> http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSa… >I can't reach that (very ancient) page right now, but... The documentation for this is example is the same in the latest v1.48 release. >> // thread A >> p3 = p2; // reads p2, writes p3 >> >> // thread B >> // p2 goes out of scope: undefined, the destructor is considered a "write >> access" >> >> shared_ptr isn't completely thread-safe for simultaneous read and >> write/destruct access? The same would presumbly apply to shared_array? >> Maybe I've missed something, are there compile-time configuration >> options to determine level of safety? >shared_ptr<T> is almost exactly as threadsafe as T* is. In this case, >thread A has a reference to an object on B's stack. That object is >called p2. If thread A tries to use that object's value while the >object is being destroyed, yeah, that's a race condition. >The way to avoid this situation is for thread B to pass p2 to thread A >by value, thus creating p2a, which thread A can read without concern. >Now there's no race condition. Note: this change does /not/ cause the T >object held by p2 to be copied. Thanks, I think my confusion arose from my inferring that the P2 in thread A in this example was shorthand for P2a, i.e., a copy of the actual P2 in thread B. Makes sense as per your interpretation. Regards, T.

1 0

[Boost.Poly] Runtime Concepts
by Thomas Jordan 08 Jan '12

08 Jan '12

Hi, Forgive me if this post strays into territory beyond Boost, but I was looking at the Adobe library http://stlab.adobe.com/group__poly__related.html and some of the research papers by Sean Parent et al. describing it, which I guess many people on this list will be familiar with. Is there any reason why this library/something akin has not been put into Boost? Is it simply that it will always live in Adobe Source Libraries and there is no point duplicating in Boost? Second question - the research papers on this seemed to peter out around 2009, is there any further work going on, or has this approach been taken as far as deemed interesting, or even been informally deprecated in favour of something else? Regards, T.

4 3

[Boost.smart_ptr] Thread Safety
by Thomas Jordan 08 Jan '12

08 Jan '12

Sorry, please ignore my previous post - finger trouble. The question is as follows: ------ Hi, Is shared_array completely thread-safe, including destruction/reference counting? From the code in /boost/detail/sp_counted_base_pt.hpp it looks like it probably is but according to http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSa… // thread A p3 = p2; // reads p2, writes p3 // thread B // p2 goes out of scope: undefined, the destructor is considered a "write access" shared_ptr isn't completely thread-safe for simultaneous read and write/destruct access? The same would presumbly apply to shared_array? Maybe I've missed something, are there compile-time configuration options to determine level of safety? Regards, T.

2 1

[Boost.Move] [Boost.Container] Compiling with older version of Boost and performance
by Thomas Jordan 07 Jan '12

07 Jan '12

Hi, I am interested in experimenting with v1.48 Boost.Move and Boost.Container. However, I am otherwise constrained to using Boost libraries v1.33.1 with a Sun C++ v5.10 compiler. I couldn't seem any 'Boost library dependencies' listed in the Move/Container documentation, but a quick look through the header files suggests that it is mainly MPL and Type Traits. So... First question: would it be feasible for me to combine the headers for these two libraries with the v1.33.1 libraries and get it to work (albeit maybe with a little customisation), or would it be a big job/non-starter? Second question - I don't see any performance analysis published for Boost.Move. I know that move semantics is about more than improved performance, but am interested in that side of things, especially as the above compiler appears suboptimal in terms of copy elision and RVO. I am wondering for example whether are there any (compiler-specific) factors which could mitigate against the performance benefits of doing a move vs a copy of a vector, using these libraries, for example. Regards, T.

2 1

[Boost.smart_ptr] Thread Safety
by Thomas Jordan 07 Jan '12

07 Jan '12

Hi, Is shared_array completely thread-safe. including destruction/reference counting? http://www.boost.org/doc/libs/1_33_1/libs/smart_ptr/shared_ptr.htm#ThreadSa… // thread A p3 = p2; // reads p2, writes p3 // thread B // p2 goes out of scope: undefined, the destructor is considered a "write access" /bb/source/boost/boost_1_33_1/boost/detail/sp_counted_base_pt.hpp

1 0

On the lack of manpower: (Apache stdcxx)
by Jim Bell 07 Jan '12

07 Jan '12

Though this isn't news, I just came across it and it speaks to our common problem. (And it's of interest to boost users in general.) Note that ARM and Sun are even invested in stdcxx to some extent. From Apache's C++ Standard Library project <http://stdcxx.apache.org/status/2011-02.txt>: Stdcxx continues to be dormant. All but [1] committer have moved on to other projects. The only remaining committer (the VP of the project) is too busy with his day job to make even small changes, or to put out the long-awaited patch release, stdcxx 4.2.2. A number of users and organizations have been using the project and expressed interest in contributing to it. Several submitted patches, others have offered help with the project build and test infrastructure. Unfortunately, since no committer is available to review patches and guide the contributors through the ASF process to enable them to gain commit privileges there seems to be little hope of reviving stdcxx. A possible solution that would allow contributions to resume is to grant commit privileges to the handful of contributors who have already submitted some patches or expressed serious interest in contributing going forward. Another alternative is to move stdcxx to a repository outside of ASF such as SPI (http://www.spi-inc.org/) where interested developers could start committing changes on their own right away, without going through the "training" process. This seems to the preferred solution among at least some of the interested users. Are there any other options? Future plans: Unless the issue with contributions can be resolved in the next quarter I suggest to retire the project.

5 6