October 2004 - Boost - lists.preview.boost.org

[jamboost] Boost.Build V2, Milestone 10 released
by Vladimir Prus 04 Nov '06

04 Nov '06

I'm pleased to announce that the next milestone release of Boost.Build V2 is available at http://prdownloads.sourceforge.net/boost/boost-build-2.0-m10.tar.bz2 http://prdownloads.sourceforge.net/boost/boost-build-2.0-m10.zip See also http://boost.org/boost-build2/ for online docs (a copy is included in distribution). Due to large number of improvements all users are encouraged to upgrade. Changes in this release: Many toolsets were added: Intel, Metrowerks, Comeau, aCC, vacpp. Documentation was converted to BoostBook and improved. Performance was improved. - Toolsets initialization syntax is much more uniform. Compiler and linker flags can now be specified. - The algorithm for computing build properties was improved. Conditional requirements can be chained, and a number of bugs were fixed. - Specific order of properties can be specified. - The main target rules can be called from everywhere, not necessary from Jamfile. - Check for "unused sources" removed. - The <library> feature affects only linking now. - The <file> feature now works only for libraries. - Simpler syntax for "searched" libraries was added. - New <dependency> feature. Unix: The right order of static libraries on Unix is automatically computed. The <hardcode-dll-paths> feature is the default. gcc: The -fPIC option is passed when creating shared libraries. Problems with distcc were solved. Sun: It's now possible to use the sun linker (as opposed to gnu), and to compile C files. Darwin: Shared libraries are now supported. MSVC: Before resource files compilation, the setup script is invoked. Options deprecated in 8.0 are not longer used. The following bugs were fixed: - The <unit-test> rule did not handle the <library> property. - Don't add "bin" to the build directory explicitly specified by the user. - Allow <include-type> to select staged targets, even with <traverse-dependencies>off. - Includes for the form '# include <whatever>" did not work. - (Qt) Add paths to all dependent libs to uic command line, which helps if the UI files uses plugins. - Using <toolset-msvc:version>xxx in requirements was broken. - Error message printed when target can be found is much more clear. - Inline targets in sources of 'stage' did not work. - Don't produce 'independent target' warnings on Windows - (gcc) The <link-runtime>static did not work. - (gcc) Suppress warnings from the 'ar' tool on some systems. - (gcc) Don't try to set soname on NT. Developer visible changes: - Generator priorities are gone, explicit overrides are used. - 'Active' features were removed - Support for VMS paths was added. Thanks to Christopher Currie, Pedro Ferreira, Philipp Frauenfelder, Andre Hentz, Jurgen Hunold, Toon Knapen, Johan Nilsson, Alexey Pakhunov, Brock Peabody, Michael Stevens and Zbynek Winkler who contributed code to this release. - Volodya

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[Python] Slice test fails on Intel 8.1 at runtime
by Stefan Slapeta 23 Oct '06

23 Oct '06

This is not a new failure, but the failure is reported for the first time. Please could anybody have a look at it? See http://tinyurl.com/4n2fx Thanks, Stefan

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New implementation of remove_xxx for vintage compilers
by Peder Holt 28 Mar '06

28 Mar '06

Hi. I have started implementing some of the missing type_traits functionality for vintage compilers using typeof. The following are complete, and seem to work flawlessly on VC 6.5 and 7.0: remove_pointer remove_reference remove_bounds The source is available at: http://groups.yahoo.com/group/boost/files/typeof_vintage.zip The use of typeof in this respect, makes remove_xxx much more flexible. Would it be possible to start using this scheme for compilers without partial template specialization support? #define BOOST_MAX_TYPEOF_SIZE 20 #include <boost/test/minimal.hpp> //Include typeof_define.hpp in all header files where new types are added to typeof. #include <boost/typeof/typeof_define.hpp> #include <complex> #include <boost/type_traits/remove_reference.hpp> #include <boost/type_traits/remove_pointer.hpp> #include <boost/type_traits/remove_bounds.hpp> #include <boost/type_traits/is_same.hpp> template<typename A0> struct X {}; template<typename A0,unsigned int A1> struct Y {}; template<typename A0,typename A1,long A2> struct Z {}; BOOST_TYPEOF_DEFINE_TEMPLATE(X,1,(typename)) BOOST_TYPEOF_DEFINE_TEMPLATE(Y,2,(typename,unsigned int)) BOOST_TYPEOF_DEFINE_TEMPLATE(Z,3,(typename,typename,long)) BOOST_TYPEOF_DEFINE_TEMPLATE(std::complex,1,(typename)) int test_main(int, char*[]) { BOOST_TEST((boost::is_same<X<int>* const[8][9],boost::remove_bounds<X<int>* const[5][8][9]>::type>::value)); BOOST_TEST((boost::is_same<Z<X<double&>,Y<bool[4][7],12324>,0>* const*,boost::remove_pointer<Z<X<double&>,Y<bool[4][7],12324>,0>* const**volatile>::type>::value)); //VC7.1 fails to compile remove_reference. BOOST_TEST((boost::is_same<Y<int,345>** const,boost::remove_reference<Y<int,345>** const&>::type>::value)); typedef BOOST_TYPEOF(5.+std::complex<double>(6,7)) result_type; BOOST_TEST((boost::is_same<result_type,std::complex<double> >::value)); return 0; } -- Peder Holt

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[signals] Performance
by Jody Hagins 04 Apr '05

04 Apr '05

Are there any docs which describe the performance of the signal/slot library? I was about to embark on a performance study because I want to use it in a very high performance critical code path, but I thought I'd ask if anyone else may have already done some work in this area. Thanks!

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RE: [boost] Call for Volunteers: the Synopsis project
by Stefan Seefeld 30 Mar '05

30 Mar '05

Hi Volodya, > From: Vladimir Prus [mailto:ghost@cs.msu.su] > Sent: September 30, 2004 03:04 > Count me as interested. Are you going to base that parser on > OpenC++, which, > IIRC, was used by Synopsis some time ago? Last time a looked > at OpenC++, it > did not even distinguish between ordinary names and > typenames, which makes me > wonder if it's a good parser. You are right, there remains a lot of work to be done. The C++ parser backend of synopsis which we are talking about here is indeed based on OpenC++, but has already undergone lots of improvements. In its original design the parser didn't contain any form of semantic analysis such as symbol lookup to disambiguate certain expressions. For what it had been used so far it was good enough. I'm now working on the features that allow it to get closer to the standard, i.e. constant expression evaluation, symbol (type) lookup, etc. As I said, any help would be very appreciated ! Regards, Stefan

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StringAlgo::split issue
by Dirk Gregorius 29 Jan '05

29 Jan '05

Hi, I used the split function on the following string: vector<string> tokens; string str= "( 448 448 64 ) ( 448 0 64 ) ( 0 448 64 ) name 0 0 0 0.5 0.5 0 0 0"; split( tokens, str, is_any_of( ()), token_compress_on ); // I pass 'space' , '(' and ')' into is_any_of() I was supposed to get 18 tokens. The first nine values, the string "name" and the remaining eight digits. "split" always returns a string vector containing 19 tokens, where the first element of the vector is an empty string. Why does the function insert empty strings into the collection? Can I use split to obtain the 18 wanted tokens? -Dirk

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Name checking in filesystem
by Walter Landry 08 Dec '04

08 Dec '04

Greetings, I have come across an annoying problem with the filesystem library. I have wrapped filesystem with Swig so that I can call it from python. I had to rewrite the filesystem::path implementation a little because Swig can't handle nested classes. In any case, once I got that sorted out, I wanted to do something like p=path(".bar") which doesn't work because filenames starting with a period are not allowed by the default name checking routine. Argh. Unfortunately, I can't figure out how to change the default name checker from python. If I worked at it long enough, I could probably work it out. But I am sure that I don't want to have to run something like path.default_name_check(no_check) at the beginning of every 10 line script. It is a particular piece of functionality (name checking) that just gets in the way. I would wager that most people using boost::filesystem from scripts would not want to have to deal with it, since it is completely different from every other portable, cross platform filesystem API. So to make a long story short, I think the default for boost::filesystem should be not to check for "portable" paths. This is different from a position I took earlier, where I thought that it is ok if I only have to set it once at the beginning. That is acceptable for large programs, but not for small ones. Regards, Walter Landry wlandry(a)ucsd.edu

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[graph] non-recursive version of undirected_dfs
by Synge Todo 24 Nov '04

24 Nov '04

Dear Boosters, I'm posting a non-recursive version of undirected_dfs, which should have advantages in space and time over the current implementation based on recursion, especially for huge graphs. It's a direct counterpart of the non-recursive version of depth_first_search for digraphs. I have confirmed that libs/graph/example/undirected_dfs.cpp as well as my own programs using undirected_dfs reproduce the identical outputs as those with the original recursive version. Best regards, Synge *** boost/graph/undirected_dfs.hpp 6 Aug 2004 05:02:41 -0000 1.1.1.1 --- boost/graph/undirected_dfs.hpp 19 Aug 2004 05:11:32 -0000 1.2 *************** *** 28,38 **** --- 28,106 ---- #define BOOST_GRAPH_UNDIRECTED_DFS_HPP #include <boost/graph/depth_first_search.hpp> + #include <vector> namespace boost { namespace detail { + // Define BOOST_RECURSIVE_DFS to use older, recursive version. + // It is retained for a while in order to perform performance + // comparison. + #ifndef BOOST_RECURSIVE_DFS + + template <typename IncidenceGraph, typename DFSVisitor, + typename VertexColorMap, typename EdgeColorMap> + void undir_dfv_impl + (const IncidenceGraph& g, + typename graph_traits<IncidenceGraph>::vertex_descriptor u, + DFSVisitor& vis, + VertexColorMap vertex_color, + EdgeColorMap edge_color) + { + function_requires<IncidenceGraphConcept<IncidenceGraph> >(); + function_requires<DFSVisitorConcept<DFSVisitor, IncidenceGraph> >(); + typedef typename graph_traits<IncidenceGraph>::vertex_descriptor Vertex; + typedef typename graph_traits<IncidenceGraph>::edge_descriptor Edge; + function_requires<ReadWritePropertyMapConcept<VertexColorMap,Vertex> >(); + function_requires<ReadWritePropertyMapConcept<EdgeColorMap,Edge> >(); + typedef typename property_traits<VertexColorMap>::value_type ColorValue; + typedef typename property_traits<EdgeColorMap>::value_type EColorValue; + function_requires< ColorValueConcept<ColorValue> >(); + function_requires< ColorValueConcept<EColorValue> >(); + typedef color_traits<ColorValue> Color; + typedef color_traits<EColorValue> EColor; + typedef typename graph_traits<IncidenceGraph>::out_edge_iterator Iter; + typedef std::pair<Vertex, std::pair<Iter, Iter> > VertexInfo; + + std::vector<VertexInfo> stack; + + put(vertex_color, u, Color::gray()); + vis.discover_vertex(u, g); + stack.push_back(std::make_pair(u, out_edges(u, g))); + while (!stack.empty()) { + VertexInfo& back = stack.back(); + u = back.first; + Iter ei, ei_end; + tie(ei, ei_end) = back.second; + stack.pop_back(); + while (ei != ei_end) { + Vertex v = target(*ei, g); + vis.examine_edge(*ei, g); + ColorValue v_color = get(vertex_color, v); + EColorValue uv_color = get(edge_color, *ei); + put(edge_color, *ei, EColor::black()); + if (v_color == Color::white()) { + vis.tree_edge(*ei, g); + stack.push_back(std::make_pair(u, std::make_pair(++ei, ei_end))); + u = v; + put(vertex_color, u, Color::gray()); + vis.discover_vertex(u, g); + tie(ei, ei_end) = out_edges(u, g); + } else if (v_color == Color::gray()) { + if (uv_color == EColor::white()) vis.back_edge(*ei, g); + ++ei; + } else { // if (v_color == Color::black()) + ++ei; + } + } + put(vertex_color, u, Color::black()); + vis.finish_vertex(u, g); + } + } + + #else // BOOST_RECURSIVE_DFS + template <typename IncidenceGraph, typename DFSVisitor, typename VertexColorMap, typename EdgeColorMap> void undir_dfv_impl *************** *** 69,74 **** --- 137,145 ---- } put(vertex_color, u, Color::black()); vis.finish_vertex(u, g); } + + #endif // ! BOOST_RECURSIVE_DFS + } // namespace detail template <typename Graph, typename DFSVisitor,

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Any interest in a boost::glob() function?
by Angus Leeming 24 Nov '04

24 Nov '04

Dear all, I've taken Richard Johnson's glob_iterator that he posted to the list back in January and re-written it completely, using Boost.Spirit to transform the input 'glob' into an equivalent regex. The result is a 'boost::glob' function that I believe is fully POSIX-conformant. Example usage: fs::path const starting_directory("."); std::list<fs::path> const matches = boost::glob("../te?t/foo*bar", starting_directory); The docs can be browsed online at http://www.devel.lyx.org/~leeming/globbing/index.html The library can be found at http://www.devel.lyx.org/~leeming/globbing.zip It should unzip to give: boost/glob.hpp boost/detail/glob.hpp libs/glob + ensuing sub directories and files. The code has been tested on Linux (g++ 3.3.2) and on Windows using MinGW/MinSys. There are still a few "issues" that I don't know how to resolve. Any pointers would be most welcome. DOCS ==== * It would be nice to insert a table inside an itemized list item, but quickbook doesn't like doing that. I need to add a separate paragraph. * boostbook/doxygen fails to document the glob_flags enum. * I generate a BOOST_LIB_NAME.html page and would like not to. BUILD ===== I have a couple of targets, lib/glob/example/real_glob.cpp and lib/glob/test/test_real_glob.cpp that I'd like to build only on POSIX machines. (They're wrappers for the system glob function.) Any pointers on how to instruct bjam to do that? REGEX ===== One test is failing on Windows "foo[[:alpha:]]bar". It works when compiled under Linux. Is there anything I should be aware of about Boost.Regex under MinGW/MinSYS? Regards, Angus

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Boost license
by Falk Hueffner 23 Nov '04

23 Nov '04

Hi, the boost license (http://www.boost.org/LICENSE_1_0.txt) does not allow redistributing modified versions. Is that intentional or an oversight? -- Falk

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[review] Formal review of the Smart Container library ends today
by Pavol Droba 18 Nov '04

18 Nov '04

Hi All, Formal review of the Smart Container library ends today. I'd like to thank you all, that participated and offered opinions about this library. I will now take my time as the review manager to sumarize the conclusion for the final verdict. Best regards, Pavol PS: There is still a little time to submit a review if somebody is willing to do so.

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Lazy Metaprogramming Library
by Vesa Karvonen 18 Nov '04

18 Nov '04

Lazy Metaprogramming Library ============================ Vesa Karvonen vesa_karvonen(a)hotmail.com 30. October 2004 This is a minimal proof-of-concept library that shows how one can implement lazy template metaprograms. Problem ------- Most contemporary template metaprogramming libraries are strict, which means that the result of a metafunction call is evaluated completely once the metafunction is invoked. Furthermore, metafunctions are written so that the arguments they receive are assumed to be completely evaluated. In addition to strictly evaluated function calls, most strict programming languages provide lazy control structures, such as `if' and `while', that evaluate their subexpressions only when needed. In contemporary template metaprogramming libraries, there usually is no clear separation between lazy control structures and strict metafunctions, which can make programming quite confusing and burdensome. Basically, a programmer using a contemporary template metaprogramming library has to explicitly annotate the evaluation order of the metacode by carefully selecting when to invoke and when not to invoke a metafunction. The invocations can not simply be completely left out, because strict metafunction do not accept uninvoked arguments. Solution -------- The metaprogramming style used in this library is different. Metafunctions and data structures (type lists) in this library are designed to be lazy. In particular, metafunctions assume that the arguments they receive are only delayed promises to compute the actual argument once explicitly invoked. This change of style eliminates the need to constantly think about evaluation order. Metafunction invocations are only needed when a value explicitly needs to be examined. For example, the metafunction `HEAD<l>' evaluates to the head of the given list `l'. In order to do that, `HEAD' needs to explicitly invoke the parameter `l' to expose the list constructor `CONS' for pattern matching. However, and most importantly, callers of `HEAD' do not need to invoke the parameter. In theory, the style used in this library could be the ideal way to implement template metaprograms, because the C++ standard almost requires template instantiations to be cached, which means that delayed promises are actually computed only once, saving CPU time. In functional programming terms, C++ implementations are almost required to perform memoization or graph reduction. In practice, however, the representation of type information may take a lot of memory and access to the instantiation cache isn't necessarily implemented efficiently. This can make lazy metaprograms less efficient in terms of time and space than their strict counterparts. Contents of the package ----------------------- The `inc/lazy_mpl' directory contains the library implementation. Only a minimal core plus a couple of higher-order functions on lists are provided. The `test' directory contains a couple of ad hoc tests demonstrating the lazy programming style and the use of lazy lists. To get most out of the code, you should take a look at the implementation of the higher-order list manipulation metafunctions `MAP', `FOLD[R|L]', `APPEND', `TAKE', `DROP', `ITERATE', `FILTER', and `ZIP_WITH'. As you can hopefully see, they are very cleanly expressed. That is how lazy metaprogramming would look like to a casually user. Future work ----------- This library is only a proof-of-concept. The intention is to show that lazy template metaprogramming is possible and can yield correct and highly readable metaprograms. The metafunctions in this library are written for clarity rather than optimized for heavy use. In particular, many of the provided metafunctions are strict in one ore more parameters, which means that those parameters are always invoked as a result of invoking the metafunction. An optimization technique called ``strictness analysis'' could be used to systematically optimize the metafunctions. The optimization would not change the way the metafunctions are used, but would change how they are evaluated internally. In some cases the optimization could be significant. Another practical issue would be to implement some sort of lambda mechanism, which would make the use of higher-order metafunctions more convenient. Copyright --------- (C) Copyright Vesa Karvonen 2004. Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE.) _________________________________________________________________ Express yourself instantly with MSN Messenger! Download today it's FREE! http://messenger.msn.com/

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[MPL] Wiki docs
by David B. Held 16 Nov '04

16 Nov '04

Here: http://www.mywikinet.com/mpl/mpl_1_32_changelog/numeric-metafunctions-proto… I'm guessing that: template< int n > struct my_int { static int const value = n; typedef my_iny type; }; is really supposed to be: template< int n > struct my_int { static int const value = n; typedef my_int type; ^^^^^^ }; And same for the "After" example. Dave

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logging lib, v1.3
by John Torjo 12 Nov '04

12 Nov '04

Dear boosters, Finally, have had some time to update the logging lib. Get it from: http://www.torjo.com/ (of course, it comes packed with docs) First of all, many thanks to Darryl Green and Caleb Epstein! Summary - solved a few bugs - redesigned so that I allow for scoped logs (no more log IDs, now logs are identified by a 'string name') - ported the code from Caleb - allow for a "log manager" (many thanks to Darryl Green!) (it is not documented yet, but will do so as soon as I have some time) - updated docs - (renaming) add_modifier_func -> add_modifier (renaming) add_logger_func -> add_appender - thread-safety update (again, many thanks to Darryl Green!) - you can log messages even *before* logs are initialized after logs are initialized, just call flush_log_cache(); As for scoped logs, to make a long story short, you'll be able to do: logger gui("app.gui") if (gui) gui.stream() << "something GUIsh"; // or (equivalent) BOOOST_SCOPEDLOG(gui) << "something GUIsh"; Still to do: - docs: write about log managers - cyclic logs Looking forward to your feedback! Best, John -- John Torjo, Contributing editor, C/C++ Users Journal -- "Win32 GUI Generics" -- generics & GUI do mix, after all -- http://www.torjo.com/win32gui/ -- v1.5 - tooltips at your fingertips (work for menus too!) + bitmap buttons (work for MessageBox too!) + tab dialogs, hyper links, lite html

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[range] warnings on vc7.1
by Jonathan Turkanis 12 Nov '04

12 Nov '04

Hi Thorsten, The program at the end of this message produces twenty C4224 Warnings ("nonstandard extension used : formal parameter 'array' was previously defined as a type") on VC7.1 and VC8.0 beta. Since Boost.Array and Boost.Range will be used together with some frequency, it might be a good idea to disable warning 4224 locally within the range headers. Best Regards, Jonathan ---------- #include <boost/array.hpp> #include <boost/range/begin.hpp> #include <boost/range/end.hpp> #include <boost/range/iterator.hpp> int main() { }

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pqs - physical quantities library
by Andy Little 10 Nov '04

10 Nov '04

Hi, I have been continuing with my physical-quantities library over the last year, http://www.servocomm.freeserve.co.uk/Cpp/physical_quantity/index.html and I am now seeking feedback as to whether it is worth putting this forward as a boost library proposal.... *Overview* The physical-quantity type-family provides methods for modeling physical-quantities in C++ programs. The advantages and extra functionality over inbuilt types used in the role include, compile time dimensional-analysis checking, automatic conversion between units and an increase in source code comprehensibility. The type family includes two types, firstly a type where the units are fixed at compile-time referred to in the text as a ct-quantity and secondly a type where the units can be run-time modified, referred to in the text as an rt-quantity. The ct-quantity has many similar features to an inbuilt-type: - concrete type with simple,consistent semantics close to those of inbuilt-types. - aims for speed and code size performance close to that of in-built types. - requires no special framework to use. *Application areas* The application areas are very wide, including scientific-engineering, CAD, 3D games programming among many others. *Future directions* 2D and 3D vector quantities, scene-graphs and scene-modelling, Graphics interface (eg OpenGL), splines and curve analysis, successive approaximation , piecewise differentiation and integration algorithms. finite element analysis, etc etc. Issues from the previous thread on the library and physical quantities in general http://aspn.activestate.com/ASPN/Mail/Message/boost/1926782 issue: Angles. current status: Angles are implemented.There are two types, irrational (ie radians) and rational fractions of revolution ie degrees minutes etc). radians are what you might call a 'weak type'. (Though this behaviour can be modified by a macro switch). They will implicitly decay to (say) double and can be implicitly cast to double. However they also allow implicit conversions to and from degrees etc. hence an implicit conversion from degrees to radians can occur if a function has a radians argument, but not a double argument. They are also useful for output of units. --------------------- issue: Differentiating different but dimensionally equivalent types. current status: This is implemented. --------------------- issue: Implicit conversions between units. current status: Implicit conversions are intrinsic. They are practical instinctive and useful. --------------------- issue: You should be using mpl. current status: Hopefully I will be able to get hold of the metaprogramming book soon, at which point I can decide whether there are advantages. --------------------- regards Andy Little

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Shortcut regex notation
by Schalk_Cronje＠McAfee.com 08 Nov '04

08 Nov '04

Would anyone be interested in having a perl-like regex shortcut notation? The original idea was born during a local C++ focus group discussion. Looking further into the feasibility I thought that this might be a useful addition to Boost. Possibly something like the following (from some proof-of-concept code) using namespace boost::short_regex; std::string str("And he said: 'BLAH BLAH'"); // [1] Substitutes first occurrence and copy (calls boost::regex_replace) // perl: ($s2=$str) =~ s/(BLAH)/Hooray/; std::string s2= _s / "(BLAH)" / "Hooray" / str; // [2] Substitute globally and copy // perl: ($s2=$str) =~ s/(BLAH)/Hooray/g; s2= _s / "(BLAH)" / "Hooray" / _g / str; // [3] Substitute first occurrence in-place // perl: $str=~ s/(BLAH)/Hooray/; ~_s/ "(BLAH)" / "Hooray" / str; In the above _s and _g are special placeholder/tag objects sort of like _1,_2. Other could include _i (case-insensitive), _m (string as multiple lines) and _s (string as single line). Multiple modifiers can be added using (,) // [4] Substitute globally and copy // perl: ($s2=$str) =~ s/(BLAH)/Hooray/gi; s2= _s / "(BLAH)" / "Hooray" / (_g,_i) / str; The purpose will not be to shortcut all of the boost.regex functionality, just the common cases, as in perl or sed. Cases [1] and [3] is very close to the perl and would be easy to understand, however [2] and [4] is moving away from perl-syntax. This might be considered illegible by some.

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[regex] any interest in finite automata-based regex engine?
by Vladimir Pozdyayev 08 Nov '04

08 Nov '04

Hello. Are there any plans to add finite automata-based subengine to the regex library? If there are, I can submit the algorithm/implementation of a modified nondeterministic FA which takes care of * greedy and lazy quantifiers, * eagerness of the alternation operator, * non-longest matches (`best' in the Perl-ish sense with respect to greediness/laziness/eagerness), * substring capturing. All these features being included, the time cost of a match is O(N(E+C)L), where N is the number of states, E is the average epsilon-closure size per state, C is the number of capturing parentheses, and L is the input length. As far as I know that's the lowest order of time complexity in this area (corrections are welcome)---though, of course, deterministic FA would be even faster. I suppose there's no point in adding another regex library, but being able to guarantee linear time cost in an existing one would be nice. -- Best regards, Vladimir Pozdyayev.

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small library proposal -- rebind template args and function pointer types
by James Harris 04 Nov '04

04 Nov '04

Hello Boost Members, I have written a small library of meta-functions that allow rebinding of template arguments and function pointer return/argument types. I am posting in an attempt to guage interest and hopefully receive pointers on the library proposal process. The library provides the following meta-functions: rebind<int index, class rebind_type, class source_type> -- rebind template arguments rebind_func_arg<int index, class rebind_type, class func_type> -- rebind argument type of func/method ptr rebind_func_return<class rebind_type, class func_type> -- rebind return type of func/method ptr rebind_method_class<class rebind_type, class func_type> -- rebind class portion of method ptr // --- rebind<> example ------------------------------------------------ template <class A, class B, class C> class foo { }; typedef foo<int, int, int> source_type; typedef rebind<1, char, source_type>::type rebound_type; // rebound_type equates to foo<int, char, int> // --- rebind_func_arg<> example --------------------------------------- typedef int (*func_ptr)(int); typedef rebind_func_arg<0, char, func_ptr>::type rebound_type // rebound_type equates to int (*)(char) // rebind_func_args also works with pointer-to-method types // --- rebind_func_return<> example ------------------------------------ typedef int (*func_ptr)(int); typedef rebind_func_return<char, func_ptr>::type rebound_type // rebound_type equates to char (*)(int) // rebind_func_return also works with pointer-to-method types // --- rebind_method_class<class rebind_type, class func_type> --------- typedef int (foo::*method_ptr)(int); typedef rebind_method_class<bar, method_ptr>::type rebound_type; // rebound_type equates to int (bar::*)(int); -- end examples -- I have tested the code using MSVC 7.1 and GCC 3.3.2-1. Please let me know if this library would be useful to any of you, or otherwise any reason why it is not required or, of course any tips/suggestions/questions that you might have. Kind Regards, James Harris.

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RE: [boost] recursive mutex and condition
by Ben Hutchings 04 Nov '04

04 Nov '04

James Ahlborn <james.ahlborn(a)med.ge.com> wrote: > hey, > I was wondering if any of the boost developers could tell me > if recursive mutexes are supposed to work with conditions? I don't believe so. If waiting for a condition releases the mutex only once, this can result in deadlock, and if it releases the mutex completely the protected data can be seen while its invariant is broken. There seems to be no right way to use recursive mutexes with condition variables. <snip> > I'm testing this on red hat 7.3 and fedora core 2. My guess as to > why it's broken is because the boost condition uses posix recursive > mutexes There's no such thing. > internally, which also seem to fail the recursive mutex/condition > test (at least on the OS's mentioned above). Anyone have any > thoughts on this? <snip> I think you should avoid using recursive mutexes. Read <http://groups.google.com/groups?selm=3434E6BA.ABD%40zko.dec.com>. Ben.

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RE: [boost] Re: recursive mutex and condition
by Ben Hutchings 04 Nov '04

04 Nov '04

James Ahlborn <james.ahlborn(a)med.ge.com> wrote: > > Ben Hutchings <ben.hutchings <at> businesswebsoftware.com> writes: > > > I don't believe so. If waiting for a condition releases the mutex > > only once, this can result in deadlock, and if it releases the mutex > > completely the protected data can be seen while its invariant is > > broken. There seems to be no right way to use recursive mutexes > > with condition variables. > > umm, using a condition fundamentally implies releasing a mutex and > then reacquiring it. regardless of the mutex type, one needs to make > sure that the invariants are valid when the mutex is released. Yes, I understand all this. <snip> > > I think you should avoid using recursive mutexes. Read > > <http://groups.google.com/groups?selm=3434E6BA.ABD%40zko.dec.com>. > > well, i've programmed significantly in both java and c++ and i think > the poster of that comment is mistaken on many fronts. besides the > obvious bias against java and the seemingly minimal knowledge of how > "synchronized" works in java, "Minimal knowledge"? Does that mean you think he's wrong in fact, or that his opinion about its usefulness is mistaken? > i think the fundamental argument of a recursive mutex being the "lazy > man's mutex" is wrong. In any moderately complex system, trying to > avoid using recursive mutexes adds complexity to the overall design > and eventually breaks the modularity of the system. As I understand it, your reason for using a recursive mutex would be that there are functions that require a weaker invariant and may safely be called from a function that holds the mutex and has broken the normal invariant, but may also be called without the mutex being held. (If a function requires the normal invariant then you need to re-establish that before calling it, and having done so you could safely unlock the mutex, removing the need for it to be recursive.) This means that responsibility for re-establishing the normal invariant for a recursive mutex is divided up between several functions. So how can the single function that waits on the condition re-establish the invariant? Wouldn't that require a gross breach of the modularity you want? <snip> > to return to boost specifically, the implementation of > recursive_mutex and condition seem to imply their combined use. I > see no documentation which says "hey, you should only use condition > with a normal mutex", nor any compiler error when i try to do so. > i see no "fundamental" reason why a recursive mutex and a condition > should not work together (they are quite happy in java). I do. > yet, they don't work, and I'm wondering if that is intended or a > bug in boost. It looks like a documentation bug to me.

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IO Collection Framework (Output Formatters REDESIGN)
by Reece Dunn 03 Nov '04

03 Nov '04

Hi All, I have been working on the library and have got a local reimplementation of my Output Formatters library based on the review comments. There are still a few issues that need to be resolved and I would like to expand stream state support. I have created a preliminary evolution document available at: http://uk.geocities.com/msclrhd/iocoll/evolution.html that outlines what the new functionality looks like. This redesign addresses several of the issues brought up during the review. Regards, Reece _________________________________________________________________ It's fast, it's easy and it's free. Get MSN Messenger today! http://www.msn.co.uk/messenger

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FORMAL review of "Output Formatters" - results
by John Torjo 03 Nov '04

03 Nov '04

Dear all, We got a lot of feedback relating the "Output Formatters" library [1]. "Yes" votes : 4 "No" votes: 2 "Abstain" votes: 2 Conclusions: - The docs and naming of the classes/functions could certainly be improved. - Seems a lot of people want this for pretty output, testing, debugging. - People don't need this library to provide ANY input facilities - quite a few people wanted a redesign. Thus, I wil consider this library "Pending Acceptation". In other words, it's considered Accepted by default, but since it will be redesigned, a new short review will take place. Reece will redesign the library, and a new formal review will take place within 3 months from now. This review will take less time - I assume 7 days. I will talk to Tom and Reece and schedule a next review date. Best, John [1] Just in case you still want a peek at the old code: http://www.torjo.com/code/outfmt.zip (153Kb) -- John Torjo, Contributing editor, C/C++ Users Journal -- "Win32 GUI Generics" -- generics & GUI do mix, after all -- http://www.torjo.com/win32gui/ -- v1.5 - tooltips at your fingertips (work for menus too!) + bitmap buttons (work for MessageBox too!) + tab dialogs, hyper links, lite html

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Request for data-member smart pointer
by Oleg Fedtchenko 02 Nov '04

02 Nov '04

To Peter Dimov Hi, Peter Could you, please, tell if is there a smart pointer template to a class data-member. I failed to find an appropriate pointer among five ones existing in the boost. I need it for the two tasks appended. By this time, I have written an extension to intrusive_ptr to meet these needs. If you or anyone else are interested I could post it or send in person. Oleg boostoleg(a)yandex.ru Task 1) class A { public: A(){ m_wData = 0;} WORD* GetData(){ return &m_wData} A* CreateA( int nOffset){ return new A;} protected: WORD m_wData; }; main() { A aInstance; WORD* pData = aInstance.CreateA( 15)->GetData(); *pData = 57; // access violation } Task 2) class DocActiveX { protected: Tree* m_pTree; public: ~DocActiveX(){ if(m_pTree) delete m_pTree;} bool Load( const char* lpszPath); Tree* Parse(){ return m_pTree;} }; class DocDirect { protected: Tree* m_pTree; public: ~DocDirect(){ if(m_pTree) delete m_pTree;} bool Load( const char* lpszPath); Tree* Parse(){ return m_pTree;} }; class ShowExternal { public: bool Show( const Tree* pTree); }; class SomeClass { protected: Tree* m_pTree; }; void SomeClass::OnLoad() { DocActiveX* pInstance = new DocActiveX; aInstance.Load( lpszSomePath); m_pTree = aInstance.Parse(); } void SomeClass::OnShow() { ShowExternal ashow; ashow.Show( m_pTree); }

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[tuple] which version to take ?
by Patrick Kowalzick 02 Nov '04

02 Nov '04

Dear all, I am not sure which version of tuples is actual and should be used: -The version in boost/tuple is working and seems consitent to the manual on the boost homepage. -The version in boost/spirit/fusion/sequence is working too and seems to be consistent to "C++ Standard Library Technical Report". tuple_size and tuple_element exist, which do not exist in the first version. Why are there two versions? Which one shall I use? Any recommendations? Thank you, Patrick P.S.: I have another short question, and need a small hint (what to search ;) ) for kind of a "compile time for-loop". Something like this: index[0] = fw_index::template get_index< tuples::tuple_element< 0, TTuple>::type >(); index[1] = fw_index::template get_index< tuples::tuple_element< 1, TTuple>::type >(); ...

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