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is_polymorphic type_trait question
by Robert Ramey 07 Jul '04

07 Jul '04

I have the following little test program #include <boost/static_assert.hpp> #include <boost/type_traits/is_polymorphic.hpp> struct vbase { }; struct derived : public virtual vbase { }; // VC 7.1, borland 5.51 and Commeau trap here (gcc 3.2 doesn't trap here!) BOOST_STATIC_ASSERT(boost::is_polymorphic<derived>::value); // everything including gcc traps here ! BOOST_STATIC_ASSERT(boost::is_polymorphic<vbase>::value); int main(int argc, char *argv[]) { } This suggests to me that is_polymorphic returns true for a class derived virtually from a base class under the gcc compiler even though the base class has no virtual function!

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Re:RE: [boost] Does anyone have an is_virtual_base_and_derived ?
by Robert Ramey 07 Jul '04

07 Jul '04

SRobb(a)reflectionsinteractive.com > I wrote that very thing a year or so ago for the purpose of testing if a > base pointer type can be statically downcast to a derived type. My problem exactly ! So I think this is what I need. Just to prove once again that no good deed goes unpunished - a) at a very minimum I want to add a boost copyright license and for that I would need your name which wasnn't on your post. b) any chance of this getting "boostified" with a couple of tests an maybe a micro-review?. c) I notice that the type_traits already in the library are much - much more elaborate due to the variations in compilers. Any chance of this getting subjected to this kind of treatment? I'm now testing this on my problem. Robert Ramey

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Boost Mathematicians
by Tom Brinkman 07 Jul '04

07 Jul '04

What is the current status of all Boost mathmatical, statistical and econometric libraries currently in development? The collection of boost math libraries that are currently included in the library are world-class and provide a wonderful foundation to build-upon. However, many areas of advanced statistical and mathmatical inference are not currently being addressed by any of the boost libraries. Is there currently a way for those boost developers with a background in mathmatics to coordinate their efforts. If not, why not? Lets get such a discussion started. A continued and regular dialog of mathmatics as it relates to boost library development would be of great use, primaryily to avoid overaping our efforts. If your a mathmetician and agree with me that boost is a great foundation to build-upon, let the group/me know. Points for Discussion: 1) We should keep a seperate list of boost::math libraries that are currently under development and provide a forum for advanced discussions. How can we do this? 2) We need a way to attract the best mathmaticians in the world. How can we make the boost libraries an even more attractive development platform for the mathemiticians? 3) We should create a list of mathmatical algorithims and libraries that are needed. 4) We need some very basic boost specific math-tutorials for our future mathemiticans and potential library writers. 5) We need to advertise to the development community about how strong of a foundation boost is for mathmatical library development. In short, lets tell the world that this is the premiere place for advanced mathmatical library development, as I believe that it could be. Comments? Regards, Tom Brinkman __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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RE: [boost] Re: [utility] boost::reset
by jhopkin＠reflectionsinteractive.com 07 Jul '04

07 Jul '04

Daniel Frey wrote: > jhopkin(a)reflectionsinteractive.com wrote: > > The STL implementation I have been using seems to allocate a buffer on first > > insertion into any container of a given type, and frees it only when it > > feels like it (often on program shut-down). > > Sounds like a pool allocator. Question: Does .clear() for your STL > return the buffer to the pool or is it still bound to the instance? What > happens in case of the .swap()-trick? I believe .clear() and the swap trick do what's expected per instance. Specifically for vector, clear generally won't release any memory to the pool; the swap trick releases it all. James Hopkin

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RE: [boost] Does anyone have an is_virtual_base_and_derived ?
by SRobb＠reflectionsinteractive.com 07 Jul '04

07 Jul '04

I wrote that very thing a year or so ago for the purpose of testing if a base pointer type can be statically downcast to a derived type. I don't claim to have tested all permutations of its usage, but it certainly worked on the cases I was testing it with. However, it does have the unfortunate side-effect of generating an 'ambiguous base' warning on the later GCCs every time it is used with a class which inherits another non-virtually. (though the traits class still gives the correct answer) If anyone can find a way of preventing this warning, or even an alternate implementation, I'd be glad to hear it. Here is my basic implementation: #include <boost/config.hpp> #include <boost/type_traits/is_convertible.hpp> namespace is_virtual_base_and_derived_detail { #ifdef _MSC_VER #pragma warning(push) #pragma warning(disable : 4250) #endif template <typename BaseImpl, typename DerivedImpl> struct tester : public DerivedImpl, virtual public BaseImpl { tester(); tester(const tester&); }; #ifdef _MSC_VER #pragma warning(pop) #endif template <typename Base, typename Derived, bool IsBaseAndDerived> struct impl; template <typename Base, typename Derived> struct impl<Base, Derived, true> { BOOST_STATIC_CONSTANT(bool, value = sizeof(tester<Base, Derived>) == sizeof(Derived)); }; template <typename Base, typename Derived> struct impl<Base, Derived, false> { BOOST_STATIC_CONSTANT(bool, value = false); }; } template <typename Base, typename Derived> struct is_virtual_base_and_derived : is_virtual_base_and_derived_detail::impl<Base, Derived, boost::is_convertible<Derived*, Base*>::value> { }; template <typename T> struct is_virtual_base_and_derived<T, T> { BOOST_STATIC_CONSTANT(bool, value = false); }; -----Original Message----- From: boost-bounces(a)lists.boost.org [mailto:boost-bounces@lists.boost.org] On Behalf Of Robert Ramey Sent: Tuesday, July 06, 2004 6:01 PM To: boost(a)lists.boost.org Subject: [boost] Does anyone have an is_virtual_base_and_derived ? Type traits includes: ::boost::is_base_and_derived<T,U> Does anyone have a version that might be called is_virtual_base_and_derived<B, D> which would return true iff D is derived virtually from B ? Robert Ramey _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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regression tests on irix
by Toon Knapen 07 Jul '04

07 Jul '04

I'm trying to get the regression tests working again on SGI/Irix but I fail to build the html tables. Apparantly the compiler_status tool is looking for a Jamfile in the wrong place. Anybody a clue what could be happening (failing command and its output in attachment) toon generating html tables: /disk2/home/tk/boost_regression/boost/tools/regression/build/run/compiler_status --comment /disk2/home/tk/boost_regression/boost/../regression_comment.html /disk2/home/tk/boost_regression/boost cs-IRIX64.html cs-IRIX64-links.html Could not open Jamfile: /disk2/home/tk/boost_regression/Jamfile **** error return code: 1 ******** errors detected; see standard output for details ******** Failed HTML result table generation.

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Re:[boost] serialization 1.31 compilation error.
by Robert Ramey 07 Jul '04

07 Jul '04

Russell Balest wrote: >Possibly triggered by the using statement: >using namespace boost::serialization; >on line 53 of iserializer.hh , but that's a guess. Using "using" in the header was an error that was pointed out during the formal review. My current copy has fixed this a new version will be available very shortly #20. This will be guaranteed compatible with 1.31. Also very shortly the latest version will be checked into main CVS. So you can wait a little bit or remove the "using from your copy of the iserializer.hpp Robert Ramey

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Interest in strict unit style typing for physics/science calculations
by edA-qa mort-ora-y 07 Jul '04

07 Jul '04

Is there any interest in a library that performs strict type checking on values with unit quantities? The intent is to prevent operation and assigment of unlike types. For example, if A is in meters/second, and B is in seconds: -A * B results in a value with "meters" units -A / B results in a value with "meters/seconds^2" -A = B results in an exception due to a mismatch The code I have so far supports arbitrary unit types via tokens, which have to be defined for a project. Some example code looks like (with several notation options): typedef UnitValue<float> uFloat; UnitType unit_m( 1 ); //define meters type UnitType unit_s( 2 ); //define seconds type uFloat time( unit_s ); time = unit_s( 3.0f ); //3 seconds uFloat speed( unit_m / unit_s ); speed = 15 * speed.Type(); //set speed of 15m/s uFloat accel( unit_m / unit_s / unit_s ); accel = speed / time; //results in 5m/s^2 accel = speed; //throws exception, m/s != m/s^2 time = accel; //throws exception, s != m/s^2 The library has a price for performance compared to native value operations. However, part of the requirements will be a flag (a #define ) that turns off the unit processing for the code, which effectively removes the classes (replaces the UnitValue simply with typedefs of the stored type). -- edA-qa mort-ora-y Idea Architect http://disemia.com/

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Write access to the CVS repository
by Edward Diener 07 Jul '04

07 Jul '04

I wanted to correct a spelling error in one of the Boost CVS documentation files but I didn't have write access to the Boost CVS repository. Is there a way to get this ? If not, should I mention such an error on this NG or is there some other place ?

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RE: [boost] Boost.Test, failed assert output
by Glen Knowles 06 Jul '04

06 Jul '04

> From: Rozental, Gennadiy > I will see what I can do about it. If I remember correctly, > the problem is that I do not know where the error occurred. > So I have no way to print line pointing there. I could print > only line pointing where the error was caught/detected. I am > not sure it is what you want. Ideally you would point to the line, but I can simply look at the output from the assert which has the file/line info. I just want the IDE to notice that there was an error so that I'll know something went wrong. As far as I'm concerned you could make up a file and line if that's what it takes to stop the build, in fact reporting an "unknown location" would probably cause less confusion then reporting the place inside boost.test where the error was detected. Thanks, Glen

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