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

Interest in serialization library
by iwg molw5 28 Dec '12

28 Dec '12

I recently wrote a small C++11 template library to unify the specification and construction of a serializable object. The library introduces a simple template markup language used to specify the layout of data on the wire, using that specification to construct the type in question much like a named tuple. A sample of the syntax used by the library is provided below: struct Object : serializable <Object, value <NAME("Field 1"), little_endian <uint32_t>>, value <NAME("Field 2"), big_endian <uint32_t>>> { }; The library is available under the MIT license at: http://www.github.com/molw5/framework with associated documentation located at: http://molw5.github.com/framework Is there any interest in including this library in Boost?

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boost-commit list down?
by Marshall Clow 28 Dec '12

28 Dec '12

The last message I got from boost-commits was: Author: apolukhin Date: 2012-12-27 13:54:28 EST (Thu, 27 Dec 2012) New Revision: 82224 URL: http://svn.boost.org/trac/boost/changeset/82224 The archives at http://lists.boost.org/boost-commit/2012/12/date.php only go through revision 82223. -- Marshall

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[odeint] Typo in Boost.Odeint
by Michel Morin 28 Dec '12

28 Dec '12

Boost.Odeint contains nearly 200 typos! Patch attached in #7835 https://svn.boost.org/trac/boost/ticket/7835 (I don't know why but the owner of odeint is empty in the ticket.) Regards, Michel

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Re: [boost] [GitHelp] Sandbox library to GitHub
by Brian Wood 28 Dec '12

28 Dec '12

Edward Diener: > >On 12/26/2012 5:10 AM, Daniel Pfeifer wrote: >> 2012/12/26 Andrey Semashev <andrey.semashev(a)gmail.com>: >>> >>> Perhaps you didn't set up a ssh public key? >>> >>> https://help.github.com/articles/generating-ssh-keys#platform-windows >>> >>> You will also have to add the key to TortoiseGit/PuTTY. >> >> If you push over HTTPS, you don't need an ssh key. > > That sounds like what I want to do. The whole low-level business of > generating public/private keys, when I already have signed up for GitHub > with a username/password, seems silly to me. I know the Linux gurus all > love this kind of intricate stuff, but I do not. It's one command: ssh-keygen -t rsa -C "username(a)email.net" If you have Cygwin installed on Windows you can use the same command there. -- Brian Ebenezer Enterprises -- in G-d we trust. http://webEbenezer.net (651) 251-9384

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[thread] to std:: or not to std::
by Michael Caisse 27 Dec '12

27 Dec '12

There seems to be a trend to migrate boost::thread to std::thread. Has there been consideration that perhaps the user community may not want this? There are differing opinions on threads (obviously) and recent breaking changes concern me. For example, the thread destructor now calling terminate instead of detach has made the upgrade to 1.52 more troublesome than it should have been. Will the next move be to remove interruption points? We have purposely selected Boost.Thread on a few projects that are also using C++11 because we prefer the Boost.Thread behaviour and feature set. The purpose of this email isn't to debate the merit of the Boost.Thread feature set but instead to understand the future direction of the library. Can Vicente or someone provide the intended road map or general plan for the library? Thanks! michael -- Michael Caisse ciere consulting ciere.com

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Patch for functional/hash
by Thomas Heller 27 Dec '12

27 Dec '12

Hi, Attached is a patch for functional/hash. The first chunk essentially gets rid of some UB (the same technique was already applied for the remainder so this looks like an oversight). I don't remember why exactly i added the second chunk, it helps on some compilers though (I think gcc on Android). Save to apply that patch? Regards, Thomas

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[proposal] safe_ref<T>
by Fernando Pelliccioni 27 Dec '12

27 Dec '12

Hi all, The motivation is to avoid code like the following... //---------------------------------------------------------------------------- #include <iostream> #include <string> struct A { void do_something( std::string s ) const { std::cout << "do something with " << s << " and " << i_ << "\n"; } int i_ = 99; }; // unsafe traditional code struct Unsafe { void set_ref( A& a ) { a_ptr_ = std::addressof(a); } void use_ref( std::string s ) const { if (a_ptr_ != nullptr) { a_ptr_->do_something(s); } } void use_ref_2( std::string s ) const { //forgot to check for nullptr a_ptr_->do_something(s); } A* a_ptr_ = nullptr; //I can't use A& nor reference_wrapper<A>, need to be nullable. }; void f() { A a; Unsafe unsafe; unsafe.use_ref( "hello" ); //null reference, do nothing, hope! unsafe.set_ref(a); unsafe.use_ref( "hello world!" ); //not-null reference, Ok! Unsafe unsafe2; unsafe2.use_ref( "hello" ); //null reference, do nothing, hope! unsafe2.use_ref_2( "hello" ); //null reference, Ops! } //---------------------------------------------------------------------------- The proposed solution: //---------------------------------------------------------------------------- // Proposed (draft) //---------------------------------------------------------------------------- template <typename T> class safe_ref { public: typedef T type; explicit safe_ref() : t_( nullptr ) {} explicit safe_ref(T& t) : t_( std::addressof(t) ) {} template <typename Func> void use ( Func f ) const { if ( is_initialized() ) { f( *t_ ); } } private: bool is_initialized() const { return t_ != nullptr; } T* t_; }; template <typename T> inline safe_ref<T> const ref(T& t) { return safe_ref<T>(t); } template <typename T> inline safe_ref<T const> const cref(T const& t) { return safe_ref<T const>(t); } //---------------------------------------------------------------------------- // Usage //---------------------------------------------------------------------------- #include <iostream> #include <string> struct A { void do_something( std::string s ) const { std::cout << "A::do_something with " << s << " and " << i_ << "\n"; } int i_ = 99; }; struct Safe { void set_ref( A& a ) { a_ref_ = ref(a); } void use_ref( std::string s ) const { a_ref_.use( [&s] ( A& a ) { a.do_something(s); }); } safe_ref<A> a_ref_; }; void usage1() { A a; Safe safe; safe.use_ref( "hello" ); //null reference, do nothing safe.set_ref(a); safe.use_ref( "hello world!" ); //safe reference, Ok! } void usage2() { safe_ref<int> si; si.use( [] (int& i ) { std::cout << i << std::endl; }); int temp = 15; safe_ref<int> si2(temp); si2.use( [] (int& i ) { std::cout << i << std::endl; }); si = ref(temp); si.use( [] (int& i ) { std::cout << i << std::endl; }); } //---------------------------------------------------------------------------- It is similar to optional<T>, but in this case the idea is to not allow access to internal data if the pointer is null, only allowing a safe usage There is interest to add something like this to Boost? Any comments or remarks? Thanks and regards, Fernando Pelliccioni.

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[GitHelp] Sandbox library to GitHub
by Edward Diener 27 Dec '12

27 Dec '12

Under Windows following the instructions at https://svn.boost.org/trac/boost/wiki/ExtractSandbox for moving an SVN sandbox library to GitHub I am successful in the first step of cloning SVN sandbox library to a temporary local directory. But when I go to that local directory and try: git push --mirror git@github.com:eldiener/variadic_macro_data.git I receive a PuTTY message of: "Disconnected: No supported authentication methods available (server sent: publickey)" I have no idea how PuTTY gets into this. I am using TortoiseGit and Git for Windows and evidently getting Git to work under Windows is difficult in some way. Anybody have any idea how to straighten this out ?

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[git] What about unmaintained libraries?
by Andrey Semashev 26 Dec '12

26 Dec '12

Hi, I have little experience with git and none with GitHub, so apologies if my questions sound silly. We have a number of unmaintained libraries in Boost. With svn anyone with commit rights can apply fixes and even take over these libs. In the end of the day, I think, this is a good thing - community support is better than no support. Even with maintained libs, it is sometimes simpler to just apply the fix instead of filing a ticket and waiting for the maintainer to get to it. Also, remember the bug fixing weeks we had a while ago - anyone could choose a library and resolve tickets against it. I'm not sure how this will work after transition to git. IIUC, every lib will be extracted into a separate git repository, and presumably only the library maintainer will have the commit rights to that repo. Essentially this means that unmaintained libs will become immutable after the transition. Also, every minor fix will have to go through the library maintainer, however busy he may be. I suppose the problem with unmaintained libs could be solved by forking but what if noone is ready to become the official maintainer but occasionally people commit fixes and improvements to the lib? I believe, at least Boost.DateTime is currently in such situation. Also, forking does not solve the problem for minor fixes to maintained libs. I would really like it if there was some kind of a user group (of all Boost maintainers) that could be used to grant commit rights to the libraries. Whatever the git term is, by "commit" here I mean the ability to publish the changes to the repository on GitHub, so that they are visible to other developers, including monolithic Boost release scripts. Is this possible? If yes, I think all repositories produced as a result of the transition to git should grant commit rights to this group by default, so that the access rights are the same as with svn now.

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[move] uninitialized_move
by Adam Wulkiewicz 26 Dec '12

26 Dec '12

Hi, I recently saw how boost::uninitialized_move is implemented, it doesn't check for exceptions thrown by move ctor and don't delete already constructed objects. Is this intentional? Regards, Adam

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