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

[#pragma once]
by Sid Sacek 18 Nov '12

18 Nov '12

I've worked with the MSVC, Sun and GCC compilers. Each one of them supports #pragma once. Is there any reason to wrap this pragma within #ifdefs? Are there any compilers out there today that don't support this #pragma? #if defined( _MSC_VER ) && ( _MSC_VER >= 1020 ) # pragma once #endif Could we change this coding pattern so that it no longer looks like MSVC is being selfish? -Sid Sacek

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[config] explicit call of operator templates / msvc bug workaround
by Stefan Strasser 10 Oct '12

10 Oct '12

Hi, is there already a macro in Boost.Config that allows you to insert the "template" keyword in the following code for those compilers that require it? struct functor{ template<class T> void operator()(); }; template<class F> void g(F f){ f.template operator()<int>(); //(1) works with GCC and comeau f.operator()<int>(); //(2) works with MSVC } this apparently only applies to operator calls. MSVC accepts both (1) and (2) for regular functions. (instantiating the operator template with an object of type T as argument, like mpl::for_each does, is not an option. I can't construct T.) thanks, Stefan

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[test] Trunk broken: What happened to test_exec_monitor?
by John Maddock 21 Sep '12

21 Sep '12

Testing on Trunk is apparently broken as the test_exec_monitor target has been removed from Boost.Test Trunk as of revision #74642. A quick grep shows 22 Jamfiles and over 200 targets dependent upon this. Whats happened? John.

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[build] 1.49 unable to bootstrap boost
by yuri kilochek 12 Sep '12

12 Sep '12

Not sure if this goes here. On Windows 7, when I try to do bootstrap on a freshly unzipped boost 1.49 at the root directory, I get the following output: Building Boost.Build engine But that is as far as it gets before os terminates whatever it is doing with this (roughly translated from russian): **** STACK SIZE EXCEEDED **** **** WHILE PERFORMING RECURSION IN BATCH MODE **** Recursion depth=654, Stack usage=90 percent. **** BATCH PROCESSING ABORTED **** Is there a way to build boost bypassing this?

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[type_traits] has_equal_to< std::vector<T> > always true_
by lcaminiti 15 Jul '12

15 Jul '12

-- View this message in context: http://boost.2283326.n4.nabble.com/boost-type-traits-has-equal-to-std-vecto… Sent from the Boost - Dev mailing list archive at Nabble.com.

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hex/unhex()?
by Olaf van der Spek 19 Jun '12

19 Jun '12

Hi, Does Boost have hex/unhex() that support std::string? I can't find them and I think they'd be quite handy to have. -- Olaf

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status of sp_counted_base_solaris.hpp
by Graham Bennett 07 Jun '12

07 Jun '12

Hi all, I'm interested in getting boost::shared_ptr to use atomic ops on Solaris. I notice there is an implementation using the OS-provided atomics in boost/detail/sp_counted_base_solaris.hpp, but it doesn't seem to be included. According to this thread: http://lists.boost.org/Archives/boost/2006/07/107144.php, it seems the reason might be that it wasn't possible to come up with a proper preprocessor condition to include it on the right versions of Solaris. I'm considering modifying my boost installation to include this header on Solaris - does anyone know of any issues with the code, or can they confirm that it has been well tested? Are there any other reasons for its omission? Thanks, Graham -- Graham Bennett

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[fusion] Trouble using BOOST_FUSION_ADAPT_ADT with boost::fusion::operator<
by GOODHART, TAYLOR 17 May '12

17 May '12

Hi all, I'm attempting to adapt a third-party struct into a fusion sequence using BOOST_FUSION_ADAPT_ADT to get access to a nice operator<. Unfortunately compilation fails and I'm not sure if it's a bug or me using the library incorrectly. As best I can read the error message, it looks like the code is attempting to compare adt_attribute_proxy structs instead of the values represented by these. Below is some code that demonstrates the problem. Can anybody help me out? Thanks, Taylor #include <boost/fusion/adapted/adt/adapt_adt.hpp> #include <boost/fusion/adapted/struct/define_struct.hpp> #include <boost/fusion/adapted/struct/adapt_struct.hpp> #include <set> #include <string> #include <boost/fusion/sequence/comparison/less.hpp> struct test1 { std::string s; const std::string & getS() const { return s; } void setS( const std::string & s_) { s = s_; } }; BOOST_FUSION_ADAPT_ADT( test1, (const std::string &, const std::string &, obj.getS(), obj.setS(val)) ) BOOST_FUSION_DEFINE_STRUCT( , test2, (std::string, s) (int, a) ) struct test3 { std::string s; }; BOOST_FUSION_ADAPT_STRUCT( test3, (std::string, s) ) using boost::fusion::operator<; int main( int argc, char * argv[]) { //Fails /*std::set<test1> destinations1; destinations1.insert(test1());*/ std::set<test2> destinations2; destinations2.insert(test2()); std::set<test3> destinations3; destinations3.insert(test3()); return 0; }

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[contract] syntax redesign
by Lorenzo Caminiti 04 May '12

04 May '12

Hello all, After a long time of inactivity for Boost.Contract, I am considering how to re-design its macro syntax to make it simpler. I can eliminate a large number of extra parenthesis based on a few pp tricks I've learned in processing Boost.Local's `const bind(type)& var`. Plus, I can provide (optional) support for variadics macros so to use comma-separated pp tuplets instead of parenthesized pp sequences on preprocessors with variadics. For example, I _think_ (but I've not implemented this yet) that I can simplify the syntax like this: #include <contract.hpp> #include <vector> #include "myvector/pushable.hpp" // Wrapper class that adds contracts to std::vector. CONTRACT_CLASS( template( typename T ) class (myvector) extends( public pushable<T> ) // Subcontracting. ) { CONTRACT_CLASS_INVARIANT( empty() == (size() == 0) // More invariants here (comma separated)... ) CONTRACT_FUNCTION( public void (push_back)( (const T&) element ) precondition( size() < max_size() // More preconditions here (comma separated)... ) postcondition( auto old_size = CONTRACT_OLDOF(size()), // Old value. size() == old_size + 1 // More postconditions here (comma separated)... ) ) { vector_.push_back(element); // Implementation. } // Rest of the class here (with more contracts if needed)... public: typedef typename std::vector<T>::size_type size_type; size_type size(void) const { return vector_.size(); } size_type max_size(void) const { return vector_.max_size(); } bool empty(void) const { return vector_.empty(); } const T& back(void) const { return vector_.back(); } private: std::vector<T> vector_; }; For a side-by-side comparison with N1962 syntax: http://svn.boost.org/svn/boost/sandbox/contract/libs/contract/doc/html/inde… For a comparison of the entire std::vector (plus Boost.ConceptCheck concepts): http://svn.boost.org/svn/boost/sandbox/contract/libs/contract/doc/html/cont… For a comparison for all Boost.Contract features (plus Boost.ConceptCheck concepts and Boost.Parameter named parameters): http://svn.boost.org/svn/boost/sandbox/contract/libs/contract/doc/html/cont… (Don't pay attention to the rest of the docs that are way out of date.) A few notes: * Extra parenthesis are still needed around class and function names. * Extra parenthesis are still needed around types (like for the parameter `(T) element`) but only if the type is not a C++ keyword (no parenthesis needed aournd int, double, void, etc) or it contains a symbol (parenthesis needed if & or * are used `(int&) x`, etc). * In postconditions, the `auto old_size = CONTRACT_OLDOF(size())` only copies the vector size (and not the entire vector :)) ). Similarly, `auto result = return` can be used to access the return value for non-void functions. (The `auto ...` is parsed by the pp and it's implemented using Boost.Typeof so no C++0x is required.) * Template declaration (but not instantiation) angular parenthesis <> are replaced by round parenthesis (). All of this _should_ be implementable in pure ISO C++. What do you think? Based on the discontent that the previous "parenthesized" syntax generated among Boosters, the key question is: Would you consider this new syntax usable?? Thanks, --Lorenzo

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Re: [boost] Slow Bugs Tracker
by Olaf van der Spek 29 Apr '12

29 Apr '12

Hi, A few months ago there seemed to be plans to improve Trac. What's the status of those plans? Trac is still slow as hell. http://lists.boost.org/Archives/boost/2011/12/188639.php http://lists.boost.org/Archives/boost/2011/12/188937.php -- Olaf

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