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iterator adaptors and const correctness
by Neal D. Becker 11 Nov '04

11 Nov '04

I was struggling with const correctness and iterator adaptors. At first I was using iterator_facade. I found it difficult to get dereference to work correctly. After changing to iterator_adaptor I got things working. I'm wondering if the approach I used is "correct". I include the whole class here, because it isn't really very big. I was using a Ring class which contains an iterator, which is cycle_iterator<std::vector<Complex>::iterator>. If a Ring const& is passed I had problems with dereference. The changes I made to cycle_iterator fix this were: 1) Add templated conversion constructor to cycle_iterator, to allow implicit conversion of cycle_iterator -> const cycle_iterator. 2) Include both reference dereference() and const reference dereference() const (likewise for operator[]) So, do my changes constitute a "correct" approach to making interoperable iterators using boost::iterator_adaptor?

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General reflection library? (was: Re: GUI Library Proposal for a Proposal)
by George van den Driessche 11 Nov '04

11 Nov '04

> Message: 7 > Date: Tue, 9 Nov 2004 13:16:05 -0500 > From: Caleb Epstein <caleb.epstein(a)gmail.com> > Subject: Re: [boost] Re: GUI Library Proposal for a Proposal > To: boost(a)lists.boost.org > Message-ID: <989aceac0411091016316d09bb(a)mail.gmail.com> > Content-Type: text/plain; charset=3DUS-ASCII > > On Tue, 9 Nov 2004 17:37:15 -0000, George van den Driessche > <grebe(a)bigfoot.com> wrote: > > > Date: Tue, 9 Nov 2004 09:38:35 -0500 > > > From: Caleb Epstein <caleb.epstein(a)gmail.com> > >=20 > > > I've been toying with using the properties library Reece Dunn recentl= > y > > > submitted (in the boost-sandbox CVS) for this purpose. I've got > > > something very sketchy, but it relies on a visitor pattern to "pass" > > > type information to client code in a manner similar to Boost.Variant. > > > > > > I'd prefer a way of storing the type information for each reflectable > > > class statically, and in a generic way, e.g. something like > > > std::map<std::string, property>. This would enable the reflection > > > code could be decoupled from the reflected classes entirely and just > > > operate on this property meta-data. It would also allow client code > > > to lookup individual properties (e.g. by name) instead of having to > > > visit all of them. > > > > > > I'm stumped by how to store this information in any sort of container > > > though, since the properties are of different types. Any thoughts, o= > r > > > is this madness? > >=20 > > The properties are of different types, but the type information for > > properties will always be of the same type :) So you can generate a pro= > perty > > set for your class, that includes the dictionary that maps names to > > property_type_info structures. Each property_type_info would be > > automatically generated from the static type of the property. > > You lost me here. The property types each inherit from property_info, > but it is similarly templated on the type of object begin > stored/referenced/aliased. Are you suggesting another non-template > base class which all properties would inherit from? Spot on. Just as a property_set corresponds to a C++ type, the property_type_info entries in the property_set each correspond to a pointer-to-member (or a pair of pointer-to-member-function if you want to wrap your property with get/set methods). Just as you generate a unique property set for each reflected type, you generate a unique property_info for each of its properties. But since each property_info has a common base class, you can stick them all in the same property set. Take a peek into the Boost.Python stuff. It follows a similar pattern, I believe. > What might this > look like? I find myself unable to write an overview of it and not almost all of it. So I'll have to write the whole thing this evening when I have time :) > What mechanism would you use to keep track of the type > information? Type information of what? You can pass around a fat pointer class which is basically a pair< void*, property_set* > when you need to maintain knowledge of the type of a pointer. I'll try to get it all written up into an understandable form this evening. George

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RE: [boost] boost::ref simple question
by Michiel Salters 11 Nov '04

11 Nov '04

The boost::function template works with boost::ref according to the docs, so try boost::function< int ( int ) > ( boost::ref( Op() ) ) HTH, Michiel Salters > -----Original Message----- > From: boost-bounces(a)lists.boost.org > [mailto:boost-bounces@lists.boost.org]On Behalf Of Neal D. Becker > Sent: maandag 8 november 2004 16:16 > To: boost(a)lists.boost.org > Subject: [boost] boost::ref simple question > > > This must be a common question. > > I want to use std::transform with a function object that is > expensive to > copy, so I want to pass by reference. I tried to use > boost::ref for this, > but this simple test doesn't work: > > struct Op { > int operator() (int x) { return 1 + x;} > Op() {} > private: > Op (const Op&); > > }; > > int main() { > vector<int> x (4); > vector<int> y (4); > Op o; > std::transform (x.begin(), x.end(), y.begin(), boost::ref(o)); > } > > Any suggestion? > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > This e-mail and any attachment is for authorised use by the intended recipient(s) only. It may contain proprietary material, confidential information and/or be subject to legal privilege. It should not be copied, disclosed to, retained or used by, any other party. If you are not an intended recipient then please promptly delete this e-mail and any attachment and all copies and inform the sender. Thank you.

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License use for non-Boost projects
by Andrew Cox 11 Nov '04

11 Nov '04

Can I release my own non-Boost projects under the Boost license? Does the Boost organisation mind? Is the license valid if I use the standard application of it in src and header files as follows? // Copyright 2004 Joe Coder. // Distributed under the Boost Software License, Version 1.0. (See // accompanying file LICENSE_1_0.txt or copy at // http://www.boost.org/LICENSE_1_0.txt) Thanks, Andrew Cox Programming projects: http://www.btinternet.com/~ahcox/index.html UCL work: http://www.cs.ucl.ac.uk/students/Andrew.Cox/

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[fileststem]1.32: with serilization: visibility of m_path
by Francis ANDRE 11 Nov '04

11 Nov '04

Hi In order to serialize a derivative class of boost/filesystem/path, one cannot access the base class member m_path without changing its visibility from private to protected: I would suggest to change the visibility of this m_path member from private: to protected, or to add an implicit definition of the serialize method into the class boost::filesystem::path. #include <boost/filesystem/path.hpp> namespace boost { namespace serialization { class access; }} class OSD : public boost::filesystem::path { private: friend class boost::serialization::access; friend std::ostream & operator<<(std::ostream &os, const OSD&); template<class Archive> void serialize(Archive &ar, const unsigned int version) { ar & m_path; } }; Regards Francis ANDRE

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boost lambda'sl bind tries to instantiate abstract classes
by Eyal Farago 11 Nov '04

11 Nov '04

MSVC 7.1 chokes when I'm trying to (bll) bind a method/function with an argument which is (const/mutable)reference to an abstract type. I've attached a simple test file and MSVC 7.1 complaints. <<lambda_tester.cpp>> <<lambda_tester_compilation.txt>> eyal.

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License and new version
by Jared McIntyre 11 Nov '04

11 Nov '04

I'm guessing from reading through the 1.32 tarball docs that the this release will still have some libraries that are not under the Boost 1 license. Is this the case? If so, is there a definitive list of these projects? Jared McIntyre

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RE: [boost] Library TR draft available
by Randy Bowen 10 Nov '04

10 Nov '04

Is there a problem with that site? I've yet to be able to download the document, or even fully load the index page on which it's referenced. > -----Original Message----- > From: Beman Dawes [mailto:bdawes@acm.org] > Sent: Tuesday, November 09, 2004 5:39 PM > To: Boost mailing list > Subject: [boost] Library TR draft available > > The latest draft of the C++ Standard Library Technical Report > is now available at > http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2004/n1711.pdf > > There may be editorial (non-substantiative) changes to the > final version of the TR document, but this latest draft is > believed to be final in terms of technical content. Thus it > should be safe for implementors or users to write code based > on this latest draft. > > It will be several years before most compilers come with a > full implementation of the TR. But some vendors (Metrowerks, > for example) are already shipping a few TR components. That > brings up the question of what Boost code does during the transition. > > To insure Boost code works with various TR implementations, > some Boost code will want to use the compiler vendor's > version of the TR if the TR component required is available, > but otherwise will want to use Boost equivalent code. How do > we handle that? The TR doesn't provide in configuration > macros, so I guess we will have to roll our own. > > --Beman > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost >

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Math functions - requirements 'spec'
by Paul A Bristow 10 Nov '04

10 Nov '04

Following the view of C and C++ Working groups at Redmond that a working implementation of my proposal for math functions was a necessary condition for consideration for a TR-2 standard, I have been skirmishing with the problems of converting Stephen Moshier's Cephes code into something that works for both C++ and C. Several issues have emerged, mainly revealing my ignorance with C - a state of bliss in which I would have preferred to remain ;-) 1 Should I no longer cater for non-compliant compilers (usually old-style function specifications? I only have MSVC 8.0 available. 2 How do I check that my code is Standard C compatible (as well as C++)? 3 How do I tell whether the compiler is a C compiler or a C++ compiler (for #if ing). #if __cplusplus #if _STDC__ ... ? 4 I have compiled a module #including <cmath> OK with explicit project property "compile with C++", but when I change this to "compile with C" and no extensions so the /Za option is on the command line, it does not define __STDC__ == 1 as I have expected. What am I doing wrong. 5 Do I have to use exclusively C /* */ style comments :-((? (Or can I assume that C compilers will understand // comments?) I have also immediately come up against the problems of IEEE 754 compliance, argument checks, NaN, infs and exception throwing. 6 Should I assume IEEE 754 compliance and signal #error "Only works with IEEE compliant compilers"? How do I check with C - numeric_limits :: is_IEC559 equivalent? Or would it be foolish to rule out the some older DEC machines? 7 Do you recommend making NaN and inf checks optional? 8 How do I find if they are available, automatically but portably? 9 Can I assume isnan(float, double and long double) with C and with C++? 10 How do I detect isinf? Do I use FPclass for detecting isinf? (pos and neg?) 11 Do you recommend making throwing exceptions optional with C++? 12 Should I scrap all the hexadecimal (mainly polynomial) constants on the grounds that conforming compilers should read decimal digit strings 'correctly' - getting the nearest representable value. Is this true for both C and C++? 13 Do you also recommend making checking arguments optional (with #ifdefs)? So that those who want the ultimate in speed at any risk can switch checking off? Comments welcome. Paul PS Slightly updated versions of my TR2 proposal are at http://www.hetp.u-net.com/public/math_stats_functions_tr2_v2.doc http://www.hetp.u-net.com/public/math_stats_functions_tr2_v2.pdf Paul A Bristow Prizet Farmhouse, Kendal, Cumbria UK LA8 8AB +44 1539 561830 +44 7714 330204 mailto: pbristow(a)hetp.u-net.com

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Boost.Thread (1.32draft) -- release library not built
by James Harris 10 Nov '04

10 Nov '04

Hi All, I have just downloaded the v1.32 draft and built the thread libraries, however it seems as though only the debug static lib has been built. I'm using VC7.1 and am trying to link to "libboost_thread-vc71-mt-s-1_32.lib" which has not been built. The following files were built successfully: - libboost_thread-vc71-mt-sgd-1_32.lib - boost_thread-vc71-mt-gd-1_32.lib - boost_thread-vc71-mt-gd-1_32.dll Is there a specific reason this lib is not being built, or is it that I've missed something somewhat important during the bjam build process? TIA - James.

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