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RE: [boost] Re: Portable alternative for VS.NET __if_exists
by Brian Braatz 05 Jan '05

05 Jan '05

> -----Original Message----- > From: boost-bounces(a)lists.boost.org [mailto:boost-bounces@lists.boost.org] > On Behalf Of Roman Yakovenko > > > -----Original Message----- > > From: David Abrahams [mailto:dave@boost-consulting.com] > > Mårten Rånge wrote: > > > I'm looking for a portable version of __if_exists (VS.NET > > keyword) and > > > unfortunately google turned up nothing good. > > > > > > I use boost fairly regular and checked boost::type_traits > > but found nothing > > > that seemed to similar. > > > > > > Has anyone heard of something that can accomplish this? > > > > It might help if you described what it does. > > full explanation: > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclang/htm… > [Brian Braatz] I Find it a TAD bothersome that the link above does NOT state it is a MS specific implementation. OR - Is this something recently added to the standard I never noticed???? Anyone know?

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Anyone received Dave A's MPL book yet?
by Brian Braatz 05 Jan '05

05 Jan '05

http://www.amazon.com/exec/obidos/tg/detail/-/0321227255/102-2639086-432 8160?%5Fencoding=UTF8&v=glance I ordered it on amazon, and it now says it will arrive Feb 16th. If anyone knows of a faster way to get it, Ill cancel my amazon order. (Maybe Dave should sell them directly that we he could keep all the profit)

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RE: [boost] Re: Anyone received Dave A's MPL book yet?
by Brian Braatz 05 Jan '05

05 Jan '05

> -----Original Message----- > On Behalf Of David Abrahams > Subject: [boost] Re: Anyone received Dave A's MPL book yet? > > Brian Braatz wrote: > > http://www.amazon.com/exec/obidos/tg/detail/-/0321227255/102-2639086-432 > > 8160?%5Fencoding=UTF8&v=glance > > > > I ordered it on amazon, and it now says it will arrive Feb 16th. > > > If anyone knows of a faster way to get it, Ill cancel my amazon order. > > > > (Maybe Dave should sell them directly that we he could keep all the > > profit) > Dave Abrahams Wrote: > Correction: Dave A's and Aleksey G's MPL book. I'd consider selling [Brian Braatz] Aleksey Gurtovoy: MY APOLOGIES TO YOU. Writing a book is not a easy undertaking and helping the rest of us get better at metaprogramming is extremely cool all by itself. I am sorry I referred to the book as "DaveA's book".

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[Random] uniform_int vs. uniform_real vs. uniform_01
by Doug Gregor 05 Jan '05

05 Jan '05

I'm having a few problems dealing with uniform_real and uniform_01. The basic issue is that uniform_real does not always produce values between its min and its max. The problem consistently occurs when I'm using minstd_rand as my generator (one of the linear_congruential variants). For instance, if I write: template<typename RandomNumberGenerator> void foo(RandomNumberGenerator& gen) { uniform_int<int> rand_int(some_min_int, some_max_int); // Okay, some_min_int <= x <= some_max_int int x = rand_int(gen); uniform_real<double> rand_double(some_min_double, some_max_double); // Uh-oh, some_min_double <= y <= some_max_double doesn't always hold double y = rand_double(gen); } Looking at the source to uniform_real, the problem is obvious: result_type operator()(Engine& eng) { return eng() * (_max - _min) + _min; } uniform_real assumes that the engine returns a value in [0, 1], but doesn't check that. If this is correct (I hope it isn't!), the "obvious" answer is to use uniform_01<RandomNumberGenerator...> as input to uniform_real. However, uniform_01 is also broken in several ways: 1) It isn't a random distribution because its operator() does not accept an engine. Instead, the engine is embedded in the uniform_01 object. 2) uniform_01 stores the incoming random number generator by _value_, so the original generator "gen" does not advance. You can't even fake it with uniform_01<RandomNumberGenerator&>, because that creates reference-to-reference problems. Below is a small patch to make uniform_real<...> behave nicely. As for uniform_01: we should deprecate it in 1.33.0 and remove it afterwords, because it is hopelessly broken and not even included in the TR. Doug Index: uniform_real.hpp =================================================================== RCS file: /cvsroot/boost/boost/boost/random/uniform_real.hpp,v retrieving revision 1.14 diff -u -r1.14 uniform_real.hpp --- uniform_real.hpp 27 Jul 2004 03:43:32 -0000 1.14 +++ uniform_real.hpp 30 Dec 2004 22:11:33 -0000 @@ -50,7 +50,11 @@ void reset() { } template<class Engine> - result_type operator()(Engine& eng) { return eng() * (_max - _min) + _min; } + result_type operator()(Engine& eng) { + return static_cast<result_type>(eng() - eng.min()) + / (eng.max() - eng.min()) + * (_max - _min) + _min; + } #if !defined(BOOST_NO_OPERATORS_IN_NAMESPACE) && !defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS) template<class CharT, class Traits>

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Re: Question and idea for smart pointers
by Ion Gaztañaga 05 Jan '05

05 Jan '05

> typedef pointer_to_other<NewType>(my_smart_ptr)::type new_pointer_t; Sorry, I mean obviously, typedef pointer_to_other<MyPtr, NewPointeeType>::type new_pointer_t; Regards, /Ion

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Boost Shmem new version available in Boost Files
by Ion Gaztañaga 05 Jan '05

05 Jan '05

Hello to all, I'm announcing a new version of Boost.Shmem library. The file is in Boost Files section (Boost.Shmem.2005.01.04.zip). After some months working with other people from boost, the library has suffered some serious rework. First of all, all documentation has been ported to BoostBook format and can be built with bjam --v2 from doc directory. It has been a hard work to port from word format to boostbook, but now, the boostbook format is much nicer. Please, this is the first rough version of the documentation, so I would be glad to receive feedback about this. Regarding to library, new features have been added: -> Shared memory mapping to fixed addresses -> Templatized mutex types, so that different locking mechanisms can be used indepently from the framework -> Templatized shared memory allocation algorithm, so that the framework can be expanded with new allocation algorithms. -> Templatized pointer types in shared memory STL allocator, so that the pointer type is independent from the framework. This allows using all STL implementations with the framework if the memory is mapped in the same address in different processes. -> Use of boost preprocessor to implement a new, wider, more clear calling syntax. See documentation to see more details. -> New relative pointer types, to balance pointer size, pointed object range, etc... There are many new features in the library but I wanted to mantain this announcement short. The library has been tested in Visual C++ .NET 2003 and gcc 3.4.3 in Suse 9.2 Linux. Please, feel free to report any comment, bug or idea. Regards, Ion

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Re: [ublas] gmane news archive not updated
by Toon Knapen 05 Jan '05

05 Jan '05

Paul Baxter wrote: > I note that the gmane news interface to this list (and the other boost > lists) got stopped in mid December. The others have been restarted, but > ublas is still not showing newer posts (mailman archive is fine). I'm > afraid I don't know what's involved in restarting them.... me neither ;-( Anyone ? > Perhaps it might make sense to have an additional 'common administrator' > for the various boost mailing lists for carrying out activities common > to all lists (like restarting the feeds). I'm not suggesting the > administrator also does ublas-specific work as the current ublas team > are doing a great job. (BTW thanks for setting up the new list!) > > I also note that http://www.boost.org/more/mailing_lists.htm still > refers to the yahoo ublas list. It might be useful to update that link > as well to refer to both the mailman page and the gmane ublas news feed > in a similar way to the spirit and language bindings projects now do. Anybody can explain me the process for doing this ?

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Portable alternative for VS.NET __if_exists
by Mårten Rånge 05 Jan '05

05 Jan '05

Im looking for a portable version of __if_exists (VS.NET keyword) and unfortunately google turned up nothing good. I use boost fairly regular and checked boost::type_traits but found nothing that seemed to similar. Has anyone heard of something that can accomplish this? As a side note, I got inspired by the technique used when to enable/disable template class specializations using boost::enable_if and succeeded in creating something that managed this: struct x { typedef std::string aggregated_type; }; struct y { }; int main(int, char*) { std::cout << is_aggregated_type_available<x>::value << std::endl; std::cout << is_aggregated_type_available<y>::value << std::endl; } Prints: 1 0 Which means that x has an aggregated type named aggregated_type. Unfortunately I failed miserably when trying to test for member variables and member functions. So I thought I take my chance and post my question here. Regards, Mårten Rånge PS. I want to give a big thank-you to the boost community for putting 1.32.0 together. It was worth waiting for. PS. I attached is_aggregated_type_available in case anyone is interested. Unfortunately only tested on VS.NET 2003 and VS.NET 2005 Beta 1 but it feels like it should work on more compilers due to the similarities with the examples in boost::enable_if documentation.

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RE: [boost] Re: Portable alternative for VS.NET __if_exists
by Roman Yakovenko 05 Jan '05

05 Jan '05

> -----Original Message----- > From: David Abrahams [mailto:dave@boost-consulting.com] > Sent: Tuesday, January 04, 2005 7:42 PM > To: boost(a)lists.boost.org > Subject: [boost] Re: Portable alternative for VS.NET __if_exists > > > Mårten Rånge wrote: > > I’m looking for a portable version of __if_exists (VS.NET > keyword) and > > unfortunately google turned up nothing good. > > > > I use boost fairly regular and checked boost::type_traits > but found nothing > > that seemed to similar. > > > > Has anyone heard of something that can accomplish this? > > It might help if you described what it does. full explanation: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vclang/htm… short explanation: __if_exists allows you to conditionally include code depending on whether the specified symbol exists. __if_exist ( variable ) { statements } where: variable The symbol whose existence you want to test for. statements One or more statements to execute if variable exists. > > -- > Dave Abrahams > Boost Consulting > http://www.boost-consulting.com > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost >

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RE: [boost] Yet another variant-style type, and boost inter-library dependencies
by Brian Braatz 05 Jan '05

05 Jan '05

> -----Original Message----- > From: boost-bounces(a)lists.boost.org [mailto:boost-bounces@lists.boost.org] > On Behalf Of christopher diggins > > In general I am curious about how other boosters feel about boost library > sizes and inter-library couplings. For me this is a big obstacle to using > boost in many circumstances. It doesn't seem to be a concern at all for > the > boost community, but I wonder if other programmers have similar sentiments > and find themselves often seeking out simpler alternatives. > Hmmm.... What you "get" with boost, to me, far outweighs library dependency. If you decouple TOO much, you end up re-inventing the wheel too many times. I am currently, for example, writing a Domain Specific Language on top of boost.lambda. It would not make sense to decouple, nor does the boost dependency bother me. In some ways this is like saying that since I never use std::list<> and always use vector<> that I would like to purchase my compiler without this header. The std libraries are "standard" and you can publish code with list<> or vector<> and know it will work on people's compilers. It is in the same way that I see boost. It is something of a "standard". (though also a work in progress) It is not clear to me what the "big obstacle" is? If you are publishing an article, then say "boost 1.32 required". Maybe I am way off base, but I just don't see the issue. " For me this is a big obstacle to using > boost in many circumstances." If you could tell us about the circumstances where this is a problem, we might be able to better see where you are coming from.

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