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RE: [boost] Win32 regressions
by Rozental, Gennadiy 08 Mar '04

08 Mar '04

> Test test_tools_test - Regressions on VC++ 6.0 and 7.0. I did not make any changes lately. But from error messages it seems like has something to do with boost::bind. Peter could you please take a look. Gennadiy.

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First lambda
by David Abrahams 08 Mar '04

08 Mar '04

I just tried using the lambda library for the first time. Here's what came out of it, after some struggle: #include <boost/lambda/lambda.hpp> #include <vector> #include <numeric> using namespace boost::lambda; struct X { X() : count(1) {} unsigned long count; }; std::vector<X> xs(10); unsigned long n = std::accumulate( xs.begin(), xs.end(), 0UL, _1 + (&_2) ->* &X::count); This program adds up the "count" members in a vector of X objects. Now, no offense intended, but this is nasty. There's just too much extra syntax required for something so simple, plus you have to make the type into a pointer just so you can dereference it Before I realized I needed to take the address of _2, I had: unsigned long n = std::accumulate( xs.begin(), xs.end(), 0UL, _1 + _2 ->* &X::count); which is only slightly better (but incorrect). I realize that I can use bind: unsigned long n = std::accumulate( xs.begin(), xs.end(), 0UL, _1 + bind(&X::count,_2)); but that's slightly counter-intuitive since the order of the target object and its member pointer are reversed. It'd be nice to allow something like: unsigned long n = std::accumulate( xs.begin(), xs.end(), 0UL, _1 + _2.at(&X::count)); while if _2 were to refer to a pointer type, we could say: unsigned long n = std::accumulate( xs.begin(), xs.end(), 0UL, _1 + _2->at(&X::count)); -- Dave Abrahams Boost Consulting www.boost-consulting.com

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shared_ptr reference count
by John McGinty 08 Mar '04

08 Mar '04

Is there any reason why shared_ptr does not use atomic_count (using InterlockedIncrement, InterlockedDecrement) for the reference count? The lightweight mutex used to protect the count in the current implementation is a spin lock that sleeps when contended. Using atomic count would offer performance improvements in both the uncontended and contended cases. Regards, John McGinty

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Re: [boost]Re: Re: [serialization] non-conformance incollection_load_imp.hpp
by JOAQUIN LOPEZ MU?Z 08 Mar '04

08 Mar '04

----- Mensaje original ----- De: Aleksey Gurtovoy <agurtovoy(a)meta-comm.com> Fecha: Sábado, Marzo 6, 2004 8:17 pm Asunto: Re: [boost]Re: Re: [serialization] non-conformance incollection_load_imp.hpp > Robert Ramey wrote: > > This exchange illustrates the problem rather nicely. Its not > clear > > to me from the name "aligned_storage" that its meant to do the > same > > job as "stack_allocate" and in fact is easily confused with > other > > boost functions. I've been able to find no documentation nor > test > > nor other information. The only place its used is in variant.hpp but > > its not mentioned in the documentation of that either. There is > no > > statement in the header itself as to what it does and the code > is > > sufficiently non-trivial that it's not obvious what its supposed > to > > do. The fact that it has a parameter than stack_allocate > doesn't > > need also suggests that it's intended purpose is different from > that > > of stack_allocate. > > It doesn't, see aligned_storage's "Rationale" subsection in > http://tinyurl.com/39asx. > I don't quite get what you mean. So, does boost::aligned_storage serve as a replacement for stack_allocate? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[Boost-bugs] [ boost-Bugs-911758 ] Silent random_number_generator failure.
by SourceForge.net 08 Mar '04

08 Mar '04

Bugs item #911758, was opened at 2004-03-08 04:56 Message generated for change (Tracker Item Submitted) made by Item Submitter You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=107586&aid=911758&group_i… Category: random Group: None Status: Open Resolution: None Priority: 5 Submitted By: Cromwell Enage (expaler) Assigned to: Jens Maurer (jmaurer) Summary: Silent random_number_generator failure. Initial Comment: The test program attached to this message fails silently when attempting to execute line 54. (The test does not return, but no exceptions or errors are thrown, either.) The culprit is in <boost/random/random_number_generator.hpp>, line 52: the variate_generator's first template parameter is base_type. Changing it to base_type& will squash the bug. Cromwell Enage ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=107586&aid=911758&group_i… ------------------------------------------------------- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click _______________________________________________ Boost-bugs mailing list Boost-bugs(a)lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/boost-bugs

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RE: [boost] serialization library #17
by Hurd, Matthew 08 Mar '04

08 Mar '04

> On Behalf Of Robert Ramey > Subject: [boost] serialization library #17 > > > Robert Ramey Small doc inconsistency with libs/serialization/doc/implementation.html#othercompilerissues Intel 8.0 appears in the left hand side frame but there is no relevant section. Regards, Matt Hurd. IMPORTANT: The information contained in this email and/or its attachments is confidential. If you are not the intended recipient, please notify the sender immediately by reply and immediately delete this message and all its attachments. Any review, use, reproduction, disclosure or dissemination of this message or any attachment by an unintended recipient is strictly prohibited. Neither this message nor any attachment is intended as or should be construed as an offer, solicitation or recommendation to buy or sell any security or other financial instrument. Neither the sender, his or her employer nor any of their respective affiliates makes any warranties as to the completeness or accuracy of any of the information contained herein or that this message or any of its attachments is free of viruses.

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Re: [boost] Re: [indexed_set] volunteers wanted for testing
by JOAQUIN LOPEZ MU?Z 08 Mar '04

08 Mar '04

----- Mensaje original ----- De: Giovanni Bajo <giovannibajo(a)libero.it> Fecha: Viernes, Marzo 5, 2004 4:30 pm Asunto: [boost] Re: [indexed_set] volunteers wanted for testing > Testing on GCC 3.4 uncovers an issue. > > ../../../boost/indexed_set/index.hpp:155: error: there are no > arguments to > `final' that depend on a template parameter, so a declaration of > `final' must > be available > This happens also on all the similar lines in the same class: 161, > 177, 178, > 179. All final* members seem to be inherited from a dependent > base, so they > need to be qualified with "this->" in front of them. The same also > happens in > index_set.hpp, line 133, 459. sequenced_index.hpp: 134, 157, 175, > 176, 177, > 576, 580. > I think there are more occurrence of this but maybe they are not > excercised by > the testes. You're very right. I'll add the missing this->'s. Thanx for the tip. > > test_list_ops.cpp generates an ICE which I already submitted for > analysys. Is there a link in the GCC database that I can track? > All the other tests compile and run succesfully (after the above > fixes).-- > Giovanni Bajo > OK, thank you again. Best, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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GUI library - another one
by David Turner 07 Mar '04

07 Mar '04

Hello It seems that the idea of adding a medium-complexity GUI library to boost is popular, but that there are widely varying opinions on how it should be done. I've written a first draft of a library that fulfils most of my expectations. It's available at http://www.turn.co.za/david/gui. It supports two platforms (Win32 and GTK2), and four user interface elements or widgets (window, label, button, text-entry). The design is such that it is extremely easy to support new platforms or widgets. These are my expectations of how a good C++ GUI library should behave: 1. It should be a consistent yet thin wrapper around the platform's native functionality. 2. It should degrade gracefully in the absence of certain features on the platform. 3. It should be extensible through the factory pattern. 4. It should couple loosely with user code - this means no inheriting from an abstract Window class. 5. It should do what the user (programmer) expects, whenever possible (i.e. no leaky metaphors). 6. Widgets that contain things should behave like containers, whenever this is practical. 7. It should not use device-specific units like pixels, wherever this is practical. and finally 8. It should be extremely easy to use. The library at the link above fulfils most of these requirements. But it's not perfect. There are some interesting design choices. In many respects the most difficult design work is still to be done (list boxes, menus, drawing areas). However, the code that exists has the great advantage of working. I'd like to know what the boost community thinks before proceeding. Regards David Turner

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Boost+python building - Only 1 error to resolve...
by jeuxal_com 07 Mar '04

07 Mar '04

For win2000,msvc (vc6) Got the error (either python22 release or 2.4current source): vc-C++ bin\boost\libs\python\build\boost_python.dll\msvc\debug\inheritance.obj inheritance.cpp C:\Lib\boost_1_31_0\boost/graph/detail/adjacency_list.hpp(1055) : error C2244: 'bidirectional_graph_ move_edge' : unable to resolve function overload C:\Lib\boost_1_31_0\boost/graph/detail/adjacency_list.hpp(1057) : error C2954: template definitions C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2039: 'dm' : is not a member of '_mfi' C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2143: syntax error : missing ';' before '<' C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2501: 'dm' : missing storage-class or type specif C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2059: syntax error : ';' C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2059: syntax error : '<' C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2653: 'T' : is not a class or namespace name C:\Lib\boost_1_31_0\boost/mem_fn.hpp(315) : error C2645: no qualified name for pointer to member (fo C:\Lib\boost_1_31_0\boost/mem_fn.hpp(320) : error C2143: syntax error : missing ';' before '}' C:\Lib\boost_1_31_0\boost/mem_fn.hpp(320) : fatal error C1506: unrecoverable block scoping error Any idea? Thanks AL Same error compiling with bjam -sBOOST_ROOT=. -sTOOLS="msvc" -sPYTHON_ROOT=C:/python22 or from boost_python.dsw

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Re: Explicit Conversion Operators (N1592)
by David Abrahams 07 Mar '04

07 Mar '04

Aleksey Gurtovoy <agurtovoy(a)meta-comm.com> writes: > To: C++ extensions mailing list > Message c++std-ext-6834 > > David Abrahams writes: >> "Powell, Gary" <powellg(a)amazon.com> writes: >> >>From my reading of this paper, it would appear that this change does >> > that. I also like that the change reuses an existing keyword in what >> > would appear to be a natural extension of its use. i.e. explicit, >> > still means explicit, you have to specify not rely on the default. >> >> I haven't read the paper yet, but IMO a bigger problem is the fact >> that we don't have a single syntax for requesting an explicit >> conversion that will always be "safe". For example: >> >> T(x) // if T is a builtin type this might be a >> // reinterpret_cast >> >> static_cast<T>(x) // might be a downcast > > That's solvable, though: > > template< typename T, typename S > > T explicit_cast(S const& s, typename enable_if< is_class<T> >::type* = 0 ) > { > return T(s); > } > > template< typename T, typename S > > T explicit_cast(S const& s, typename disable_if< is_class<T> >::type* = 0) > { > return static_cast<T>(s); > } This formulation requires T (and S, if you want to pass rvalues) to have an accessible copy ctor. I'm not sure it's better than the formulation in boost/implicit_cast.hpp, which only puts a restriction on T. -- Dave Abrahams Boost Consulting www.boost-consulting.com

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