March 2012 - Boost - lists.preview.boost.org

[offtopic] C++Now! Room Reservation at Aspen Meadows
by Hartmut Kaiser 31 Mar '12

31 Mar '12

Hey all, If somebody needs a room reservation at the Aspen Meadows for C++Now in May, please get in contact with me offline. I have to cancel my trip and would like to avoid the cancellation penalty for my booked room. Regards Hartmut --------------- http://boost-spirit.com http://stellar.cct.lsu.edu

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[guideline] 31 character filenames?
by Eric Niebler 30 Mar '12

30 Mar '12

Our current guidelines[1] say filenames should not exceed 31 characters. This was recently brought to my attention by a bug[2] from someone who actually cares because he uses the ODS-2 filesystem on OpenVMS. On a lark, I hacked the inspect tool to check for too-long filenames and lo! found a bazillion. Most (but not all) violations are from doc files auto-generated by doxygen and docbook, but which nevertheless go out with the boost distribution and so should conform. (Right?) So, should we care? Considering that we have little control(?) over how doxygen and docbook generate their files? I have fixed the bug in question, but it feels like a token effort. Should we just drop support for niche filesystems like ODS-2, and close all future bugs "won't fix"? [1] http://www.boost.org/development/requirements.html [2] https://svn.boost.org/trac/boost/ticket/6196 -- Eric Niebler BoostPro Computing http://www.boostpro.com

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[Assign][GIL] Boost Assign and GIL incompatibility in gcc 4.3.2
by Andrew Hundt 29 Mar '12

29 Mar '12

The following source code compiles under clang 3.1, but fails under gcc 4.3.2 with boost version 1.46. It doesn't look like there are updates to either library in the boost news list since then. #include <vector> #include <boost/assign/std/vector.hpp> // for 'operator+=()' #include <boost/gil/gil_all.hpp> int main(int argc, char** argv){ using namespace boost::assign; std::vector<int> values; values += 1, 2, 3, 4; typedef boost::gil::rgb8_pixel_t pt; std::vector<pt> pixValues; pixValues += pt(1,2,3),pt(2,3,4); } ------------------------------------- Compiler versions: FAILED: gcc (SUSE Linux) 4.3.2 [gcc-4_3-branch revision 141291] Copyright (C) 2008 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. SUCCEEDED: Apple clang version 3.1 (tags/Apple/clang-318.0.54) (based on LLVM 3.1svn) Target: x86_64-apple-darwin11.3.0 Thread model: posix Cheers! Andrew Hundt

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Arena/Linear allocators
by Olaf van der Spek 29 Mar '12

29 Mar '12

Hi, I'm looking for arena/linear allocators, for use with multi_index, unordered_map and others. Does Boost provide anything like this? There's Boost Pool, but it only provides a singleton pool allocator. -- Olaf

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[contract] nothing special about nested classes
by lcaminiti 29 Mar '12

29 Mar '12

Hello all, In the _many_ Contract Programming references that I have read (including N1962): http://contractpp.svn.sourceforge.net/viewvc/contractpp/trunk/doc/html/cont… I didn't find anything special about contracts for nested classes. I think that is because nested classes are executed at run-time "orthogonally" with respect to their enclosing classes. In other words, nesting a class only nests it's name (and changes some visibility rules) but it does not effect the run-time execution of the class and therefore it does not affect the contracts checked for the nested class. For example, the execution of a nested class y should only check y's invariants and not also the invariants of its enclosing class x: #include <contract.hpp> #include <iostream> CONTRACT_CLASS( struct (x) // enclosing class ) { CONTRACT_CLASS_INVARIANT( std::cout << "x's invariant" << std::endl ) CONTRACT_CLASS( public struct (y) // nested class ) { CONTRACT_CLASS_INVARIANT( std::cout << "y's invariant" << std::endl ) CONTRACT_FUNCTION( public void (f) ( void ) ) {} }; }; int main ( void ) { x::y yy; yy.f(); // checks y's invariant but not x's invariant return 0; } In fact in this example an object of x is not even created. Of course, if y was to create or get an object of x and invoke x's member functions then x's contracts will be checked as usual. This makes sense to me but I thought to share it with the ML. Thanks. --Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/boost-contract-nothing-special-about-nes… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Boost Optional
by Rafael Justo 29 Mar '12

29 Mar '12

Hello! This is my first post in this list. =) I was looking today at Boost Optional (great work!). And I was wondering how could I do something like the bellow code. -------------------------------- #include <boost/optional.hpp> class Test {}; boost::optional<Test> get() { return boost::optional<Test>(); } int main() { if (get() == true) { // OK } else if (get() == false) { // ERROR } return 0; } -------------------------------- But there's no "operator==" with bool in optional.hpp, so the above code don't compile (i have checked version 1.49). Is it possible to add the patch described bellow in optional.hpp to solve this problem? -------------------------------- --- boost_1_49_0/boost/optional/optional.hpp 2010-12-18 19:29:39.000000000 -0200 +++ boost_1_49_0_new/boost/optional/optional.hpp 2012-03-28 16:03:53.417578997 -0300 @@ -616,6 +616,11 @@ return *this ; } + bool operator== (const bool condition) + { + return ((*this && condition) || (!*this && !condition)); + } + void swap( optional & arg ) { // allow for Koenig lookup -------------------------------- Best regards, Rafael Justo

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using of circular_buffer
by news.gmane.org 28 Mar '12

28 Mar '12

Hello there, i am new here and i just want to say "hi". so, i'm using boost almost a year now, usually i just used the array component. latley i wanted to implement the circular_buffer. i've defined it in a class after the private-modifier like this: boost::circular_buffer<std::string> textBuffer(10); (as take from the documentation) but my compiler on minGW will throw an error. so, i guess i got something wrong in declaring a string-textbuffer with the lenght of 10?! in the boost-docs there is following example: boost::circular_buffer<int> cb(3); help is appreciated, best would be a working example and a little hint which information is may have missed. greetings tony

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Fwd: [Boost-bugs] [Boost C++ Libraries] #380: Support for bundled properties in graph adaptors
by Marshall Clow 28 Mar '12

28 Mar '12

I just wanted everyone to notice that Jeremiah just closed a _seven year old_ bug in boost. -- Marshall Begin forwarded message: > From: "Boost C++ Libraries" <noreply(a)lists.boost.org> > Subject: Re: [Boost-bugs] [Boost C++ Libraries] #380: Support for bundled properties in graph adaptors > Date: March 28, 2012 1:47:03 PM PDT > Cc: boost-bugs(a)lists.boost.org > Reply-To: boost(a)lists.boost.org > > #380: Support for bundled properties in graph adaptors > -----------------------------------+---------------------------------------- > Reporter: dgregor | Owner: dgregor > Type: Bugs | Status: closed > Milestone: To Be Determined | Component: graph > Version: Boost Release Branch | Severity: Problem > Resolution: wontfix | Keywords: > -----------------------------------+---------------------------------------- > Changes (by jewillco): > > * status: reopened => closed > * resolution: => wontfix > > > Old description: > >> {{{ >> The graph adaptors (such as subgraph) do not support bundled >> properties, but they should. >> }}} > > New description: > > {{{ > The graph adaptors (such as subgraph) do not support bundled > properties, but they should. > }}} > > -- > > Comment: > > This is likely to work now, so closing as wontfix. Please reopen if the > problem still exists in the trunk version of Boost. > > -- > Ticket URL: <https://svn.boost.org/trac/boost/ticket/380#comment:7> > Boost C++ Libraries <http://www.boost.org/> > Boost provides free peer-reviewed portable C++ source libraries. > _______________________________________________ > Boost-bugs mailing list > Boost-bugs(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-bugs -- Marshall Marshall Clow Idio Software <mailto:mclow.lists@gmail.com> A.D. 1517: Martin Luther nails his 95 Theses to the church door and is promptly moderated down to (-1, Flamebait). -- Yu Suzuki

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DCVS vs CVS: call for constructivism
by Philippe Vaucher 28 Mar '12

28 Mar '12

Hello, I think we all know understood that there are people from both camps, some with emotional arguments, some with constructive arguments, but it's not really moving anywhere. We need to start listing what would have to be done and once we have such a map see if it's worth it before discussing pointless things. Just so we can redirect people saying things like "Nobody told me a real advantage yet" to this post, here's a recapitulation of what I think the advantages/disadvantages of a DCVS is ( http://www.ericsink.com/vcbe/html/dvcs_advantages.html, http://www.ericsink.com/vcbe/html/dvcs_weaknesses.html) Pro: - Offline work (you can use diffs, you can commit) - Speed of operations compared to svn - No need to setup a server to work locally (encourages participation (focus on working first, then sharing later)) Cons: - Cannot check out subpaths - Cannot lock files - Would require people to change their habits and learn new tools I think most people in the svn-camp will tell that with the 1.8 checkpoints feature you can now also commit while offline and thus the only advantages for DCVS seems to be speed and the ability to check all the data while offline. I think the people that are opposed to the change unfortunately won't be convinced by those arguments, even tho pretty much every who switched to DCVS will tell you that the advantages are worth it and it's more than simply speed or freedom, it's a philosophy etc. So I think the best thing to do now is first to make a map of what would have to be done if we decided to switch, to see if it's an option at all. Here's a simple draft, please participate into making it better: - Import current history - Migrate the existing hooks - Migrate the existing scripts around. - Migrate the test runners - Trac / Website integration (redmine with git extensions?) - Rights management (gitolite?) - Update release procedures Maybe we'd start a page on the wiki, but the idea is to find out if there are more steps to be done and if there's any showstopper in those steps. I think the best solution would be to offer the repository with several protocols, namely git/hg/svn so everyone could use the tool they want (e.g github offers svn/git, I know other hosts do it too). Philippe

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[Lockfree] Small compilation error with gcc -Wall
by Julien Nitard 28 Mar '12

28 Mar '12

Hi all, The following code seems to generate an "unused variable" variable warning with g++ -Wall. I am working on the latest version available from git, though I am not sure if this version is relevant. #include <boost/lockfree/fifo.hpp> typedef boost::lockfree::fifo<ReplicateData, boost::lockfree::static_freelist_t> Queue; Queue _buffer(4096); It occurs in fifo.hpp at line 263. Replacing tagged_node_ptr head2 = head_.load(memory_order_relaxed); By head_.load(memory_order_relaxed); Seems to do the job. Many thanks, Julien

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