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[asio] Removing gcc warning
by Richard Smith 19 Nov '08

19 Nov '08

The function boost::asio::detail::pipe_select_interrupter::interupt() in <boost/asio/detail/pipe_select_interrupter.hpp> produces the following warning in gcc 4.3.2 / glibc 2.8 when compiled with -O1 or higher. The warning occurs even without any -W options. ./boost/asio/detail/pipe_select_interrupter.hpp:75: warning: ignoring return value of ‘ssize_t write(int, const void*, size_t)’, declared with attribute warn_unused_result As the message implies, gcc issues this warning whenever a function declared with __attribute__((warn_unused_result)); it appears that gcc implicitly places this attribute on ::write as the glibc header doesn't contain it. A short test case is: #include <unistd.h> int main() { ::write(1, 0, 0); } To suppress the warning, the function interupt() function can be altered as follows: #include <boost/concept_check.hpp> void interrupt() { char byte = 0; ignore_unused_variable_warning( ::write(write_descriptor_, &byte, 1) ); } Is there any chance of making a change along these lines? Apologies if this is a know issue: a quick search of the mailing list didn't turn anything up. -- Richard Smith

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Boost.Build causing failures on the release branch (and Trunk too)
by John Maddock 19 Nov '08

19 Nov '08

There seem to be a lot of failures on the release branch caused by some libraries not being found, so for example on acc: http://tinyurl.com/6r76o5 or on Darwin: http://tinyurl.com/6dyezn The library not being found is part of the project requirements BTW in case that helps, Regards, John.

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[signals2][review] The review of the signals2 library (formerly thread_safe_signals) begins today, Nov 1st
by Stjepan Rajko 19 Nov '08

19 Nov '08

Hello all, The review for the Signals2 library (formerly known as thread_safe_signals) submitted by Frank Mori Hess begins today (Nov 1st) and is scheduled to end on Nov 10th. I would like to thank Franz Alt, Terry Golubiewski, Doug Gregor, Ravikiran Rajagopal and Andrew Webber for making this review possible by committing to reviewing the library. How to submit a review: -------- As usual, EVERYONE is welcome to participate in the review discussions and to submit a review. I strongly encourage participation from reviewers that would examine the library from a purely user standpoint (commenting on the interface and / or the documentation), as well as reviewers that would be willing to look into the details of the implementation (i.e., you don't have to focus on both). Here are some questions you might want to answer in your review (feel free to skip those that don't apply to your analysis): * What is your evaluation of the design? * What is your evaluation of the implementation? * What is your evaluation of the documentation? * What is your evaluation of the potential usefulness of the library? * Did you try to use the library? With what compiler? Did you have any problems? * How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? * Are you knowledgeable about the problem domain? And finally, every review should answer this question: * Do you think the library should be accepted as a Boost library? Be sure to say this explicitly so that your other comments don't obscure your overall opinion. Please submit your review either to the list or privately to me by the end of the review period. If you send me a review privately I will forward it to the list so the review can be discussed. If you would prefer me to forward your review anonymously (with your name removed) please indicate that in your e-mail. If you are a first time reviewer, here is some more information to get you started: * http://www.boost.org/community/reviews.html has more information on the review process * the review officially takes place on both the boost dev and boost-user lists, but typically more of the discussion happens on the boost dev list * if you want to get a feel for past reviews, you can find them in the archives (see http://www.boost.org/community/groups.html) - the past review dates are on the review schedule (http://www.boost.org/community/review_schedule.html) Typically, there is a period of discussion between the reviewers and the author, with official reviews coming in towards the tail end of the review period. About the library: -------- * The library can be downloaded from: http://www.boostpro.com/vault/index.php?&directory=thread_safe_signals (latest version is signals2-2008-10-08.zip) * Documentation is also available online: http://www.comedi.org/projects/signals2/libs/signals2/doc/html/index.html * A synopsis: The Boost.Signals2 library (formerly known as thread_safe_signals) is an implementation of a managed signals and slots system. Signals represent callbacks with multiple targets, and are also called publishers or events in similar systems. Signals are connected to some set of slots, which are callback receivers (also called event targets or subscribers), which are called when the signal is "emitted." Signals and slots are managed, in that signals and slots (or, more properly, objects that occur as part of the slots) can track connections and are capable of automatically disconnecting signal/slot connections when either is destroyed. This enables the user to make signal/slot connections without expending a great effort to manage the lifetimes of those connections with regard to the lifetimes of all objects involved. When signals are connected to multiple slots, there is a question regarding the relationship between the return values of the slots and the return value of the signals. Boost.Signals2 allows the user to specify the manner in which multiple return values are combined. * Relationship to Boost.Signals: This is a thread-safe variant of the original Boost.Signals library. There have been some changes to the interface to support thread-safety, mostly with respect to automatic connection management. The following thread offers some more details on the differences between the two implementations, as well as a plan of a phased replacement of Boost.Signals should Signals2 be accepted: http://tinyurl.com/4sqau3 [nabble] The Signals2 FAQ also covers some differences: http://tinyurl.com/576gl6 Kind regards, Stjepan (review manager)

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task_array<n> and variadic templates
by vicente.botet 19 Nov '08

19 Nov '08

Hi, I want to create an static task_array<n> which must be initiaized with n functors. In pseudo code: template <std::size N> struct task_array { template <typename F_1, ..., typename F_N> task_array(F_1 f1, ..., F_N fN); }; My current implementation with N=1..3 is like that template <std::size N> struct task_array; template <> struct task_array<1>; { template <typename F_1,> task_array(F_1 f1); }; template <> struct task_array<2>; { template <typename F_1, typename F_2> task_array(F_1 f1, F_2 f2); }; template <> struct task_array<3>; { template <typename F_1, typename F_2, typename F_3> task_array(F_1 f1, F_2 f2, F_3 f3); }; I can use the Boost.Preprocessor library to generate this up to a maximum know at compile time, but can I define this class with the help of variadic templates? If yes how? Thanks in advance, Vicente

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[alchemy] Boost on Adobe Alchemy
by Wilhansen Li 19 Nov '08

19 Nov '08

Hi guys, Adobe Labs just released their Alchemy ( http://labs.adobe.com/technologies/alchemy/) C/C++ to AVM2 compiler which basically compiles C/C++ code to .swf or .swc which can then be imported to Flash or Flex. I'm gonna try it out when I find some time next week. In any case, I'm interested in making Boost work in Alchemy but have no idea where to get started (aside from copy-pasting the generated header files for gcc for the header-only libraries). Is there anybody else interested in porting Boost over to Alchemy? Best Regards, Wil --

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subbitset
by Andreas Klein 19 Nov '08

19 Nov '08

Hello. I am using your dynamic_bitset and I encountered the following problem. I have realy large bits sets (>100000) bits. At some point I need do some xor Operations on only a small fraction of the bits. So I need a way to access the bits from index n to n+s-1. The bitclass has no convient way to do this. I suggest add the member function sub_bitset for that purpose. Example: a = 100000101101101001110101 ^^^^^^^ a.subbitset(3,7) b = 1001110 (The ^^^^^^^ marks the position of b in a). I implemented subbitset as follows: template<typename B, typename A> dynamic_bitset<B, A> dynamic_bitset<B, A>::subbitset(size_type n,size_type s) const { assert(n+s < size()); dynamic_bitset res(s); size_type const last = res.num_blocks() - 1; // num_blocks() is >= 1 size_type const last2 = num_blocks() - 1; size_type const div = n / bits_per_block; // div is <= last block_width_type const r = bit_index(n); const block_type * const b = &m_bits[0]; block_type * const bb = &res.m_bits[0]; if (r != 0) { block_width_type const ls = bits_per_block - r; for (size_type i = 0; i <= last; ++i) { if (div+i+1 >last2) { // Do we reach the last block? bb[i] = (b[div+i] >> r); break; } bb[i] = (b[div+i] >> r) | (b[div+i+1] << ls); } } else { for (size_type i = 0; i <= last; ++i) { if (i+div>last2) // Do we reach the last block? break; bb[i] = b[i+div]; } // note the '<=': the last iteration 'absorbs' // b[last-div] = b[last] >> 0; } // Zero unused bits block_width_type const rr = bit_index(s); if(rr != 0) bb[last] &= (1<<(block_type)(rr))-1; return res; } I guess, that I am not the only one who would benefit from the possibility to access subbitsets. I could also imagine that references to subbitsets could be of some use. Foe example I could imagine that one would use subbitset as follows. a= 00000000 b= 111 a.subbit(2,3) ^= b; -> a=00011100 But such a reference would be harder to implement and at the moment I do not need it. What do you think? Is there any hope for subbitset in boost? Best wishes Andreas Klein.

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which Operating Systems should be supported?
by Oliver Kowalke 19 Nov '08

19 Nov '08

Hello, I'd like to know which operating systems should be take into account if a new library gets contributed? Should only the newest version of the os be considered (I think not - at least on Windows). - Windows - Linux (kernel version + glibc version) - xBSD (FreeBSD, NetBSD, OpenBSD, DragonFly, .... MAC OS?) - HP/UX - Solaris, OpenSolaris (is there a difference beside the second is open source?) - AIX - what about this systems (maybe no futher activly developed): - IRIX - Tru64 special purpose os: - QNX regards, Oliver -- Der GMX SmartSurfer hilft bis zu 70% Ihrer Onlinekosten zu sparen! Ideal für Modem und ISDN: http://www.gmx.net/de/go/smartsurfer

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boost and vendor's TR1 implementations
by Sergey Sadovnikov 19 Nov '08

19 Nov '08

Hello All, Today there is at least two implementations of TR1 library extensions shipped with compilers. I mean VS 2008 SP1 and gcc 4.3.x STL. Because of boost has it's own implementation of TR1 there is some problems with migrating code to this compilers. For example: 1. There is many ambiguous names if both boost and std::tr1 exposed into global namespace. 2. boost::transform_iterator knows nothing about std::tr1::bind shipped with VS2008 compiler. I think what first problem is very serious. I sure what there is a lot of code what exposed 'boost' namespace into global scope. Some of boost test cases has such directives (tests for 'function', 'tokenizer', 'string algo' libraries for example). When developers will start to expose 'std::tr1' namespace into global scope they will be encountered many problems with compilation. I think what it will be good idea to hide boost implementation of TR1 classes when this classes shipped with compiler. For example: //... #ifdef _HAS_TR1 #include <memory> namespace boost { using std::tr1::shared_ptr; //... other usings } #else // rest of the shared_ptr.hpp #endif -- Best Regards, Sergey mailto:flex_ferrum@artberg.ru

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namespace noncopyable_
by Kenneth Laskoski 19 Nov '08

19 Nov '08

Why is this nested namespace noncopyable_ necessary? The comment "// protection from unintended ADL" seems greek to me. Can someone please enlighten me and point out a practical consequence of simply defining "namespace boost { class noncopyable {...}; }" Thanks, Kenneth

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[constrained_value] New version
by Robert Kawulak 19 Nov '08

19 Nov '08

Hi all, I've updated the Boost Constrained Value library (which is likely to be reviewed soon) -- the list of changes is below: - added unconstrained -- a new constrained alias to replace it in release mode if constraint-checking is not needed and efficiency is a concern, - added Examples section to the documentation, - other minor corrections and improvements in the documentation, - using BOOST_THROW_EXCEPTION instead of boost::throw_exception() (requires Boost version 1.37.0), - fixed one place to make a better use of EBO. As usually, the code and documentation can be downloaded here: http://rk.go.pl/f/constrained_value.zip The documentation is also available online here: http://rk.go.pl/r/constrained_value Best regards, Robert Kawulak -=##############=- "I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

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