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[iterators] request for utility iterator
by Thorsten Ottosen 14 Feb '05

14 Feb '05

Hi all, I often want to iterate over just the values of a map or perhaps just the keys of a map. Therefore I would like to see the following iterator adapters in the iterator library: template< class Map > struct map_key_iterator; template< class Map > struct map_value_iterator; template< class Map > struct map_const_value_iterator; I have outlined an implementation in the attached file, but basically it just a wrapper around transform_iterator<typename Map::iterator>. Comments? br Thorsten begin 666 map_value_iterator.cpp M(VEN8VQU9&4@/&)O;W-T+VET97)A=&]R+W1R86YS9F]R;5]I=&5R871O<BYH M<' ^#0H-"G1E;7!L871E/"!C;&%S<R!-87 @/@T*<W1R=6-T('-E;&5C=%]F M:7)S= T*>PT*(" @('1Y<&5D968@='EP96YA;64(a)36%P.CIK97E?='EP928@ M<F5S=6QT7W1Y<&4[#0H@(" @#0H@(" @<F5S=6QT7W1Y<&4@;W!E<F%T;W(H M*2@@8V]N<W0@='EP96YA;64(a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a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a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`` ` end

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Re: [boost] Re: Re: Querying the Interest in a new AutoPtr class?
by Chris Just 13 Feb '05

13 Feb '05

Jonathan Turkanis wrote: >> I wanted to create a very simple AutoPtr that was essentially the same >> as the STL auto_ptr (and backwards compatible with it). > > Unfortunately, you haven't (see below). Furthermore, auto_ptr is widely > recognized as unsafe because it is too easy to transfer ownership > unintentionally. Of course you can unintentionally transfer ownership if you don't know what you're doing. ;) I believe that's why you're not supposed to pass an auto_ptr to a function -- instead you pass the pointer itself with .get(). You can't stop everyone from shooting themselves in the foot. >>> I only looked very briefly, but I don't see how your auto_ptr can be >>> returned from functions. Also, why do you need the m_Owner variable? >> >> Correct me if I'm wrong, but wasn't there a specific reason why the >> STL auto_ptr was made so it couldn't be passed to or returned from a >> function? > > This was true of the initial version. The standard version, which is version 3, > implements a flavor of move semantics (and it doesn't quite work). I'm using the version that comes with Visual C++ 6.0, whatever version that is. >> Anyways, if you want to pass or return the pointer to/from a >> function, just use the .get() or .release() functions. > > But this subverts the resource management system. How? If you pass a pointer to a function, you shouldn't be deleting it inside that function anyways (so pass it with .get()), and if you return a pointer from a function, you can save it in a new AutoPtr so it will get deleted automatically... >> I need the m_Owner variable to tell me if I own the pointer before I >> delete it. > > For auto_ptr, checking that the stored pointer is non-null should be sufficient. I don't set my pointer to NULL when I release() it, I just set m_Owner = false. I've also run some speed comparisons between auto_ptr and AutoPtr and (on Windows at least) they appear to be virtually the same speed when doing the same operations. I'm wondering what the speed comparisons would be between auto_ptr and some of the other smart pointers that you mentioned? Chris Just __________________________________ Do you Yahoo!? Yahoo! Mail - You care about security. So do we. http://promotions.yahoo.com/new_mail

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[filesystem] Major changes before standardization
by Beman Dawes 13 Feb '05

13 Feb '05

I'm currently working on a major revision of the Boost filesystem library aimed at getting it ready to be proposed to the C++ committee for the next Library TR. The critical technical change required is internationalization. The plan is to provide a templated basic_path class, with typedefs for path and wpath. In other words, an approach very similar to the current std::basic_string, std::string, and std::wstring. Doing this adds a certain amount of complexity compared to the current path class. For example, a path_traits class has to be introduced to give basic_paths on user defined types a way to import the conversions, delimiters, and other traits. To offset the added complexity, I'd like to reduce some of the complexities in the current design: * Eliminate the distinction between native and generic grammars; either would be permitted in all contexts. As well as simplifying the class interface a bit, this will also eliminate a source of user confusion. * Move the name error checking from the basic_path class into stand alone functions. Although the current error checking could be further improved by Peter Dimov's suggested change allowing failure to be treated as either a warning or a hard error, moving it out of the class simplifies the interface, allows full path (rather than name-by-name) error checks, and eases internationalization. The primary downside of these changes will be that users who want path portability checks will have to code calls to checking functions that are currently being called automatically. The internationalization of the library is a big enough change that we will probably want to have at least a mini-review once the changes are complete. Comments? --Beman

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Strange gcc 3.2.2-5.8 behavior
by John Eddy 13 Feb '05

13 Feb '05

The following bit of code gives me an undefined symbol (l1) when using gcc 3.2.2-5.8. Is there something wrong with the code or is there a bug in the compiler or a setting I don't know about, etc? struct S { static const short l1 = 10; }; void go(const short& l) {}; // causes undefined symbol l1 int main(int argc, char* argv[]) { go(S::l1); return 0; } If I do normal, non-in-class-initialization, the problem doesn't appear nor does it appear if I accept the short by value in go. Thanks, John

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Re: [boost] Re: Querying the Interest in a new AutoPtr class?
by Chris Just 13 Feb '05

13 Feb '05

Jonathan Turkanis wrote: > There is a policy-based pointer, based on the Loki SmartPtr, coming up for > review soon which can emulate an auto_ptr and allows deletion policy to be > specified as part of the 'storage policy'. I don't know much about the Loki SmartPtr, but it sounds like it might be a little hard to use if you need to setup policies... I wanted to create a very simple AutoPtr that was essentially the same as the STL auto_ptr (and backwards compatible with it). > I only looked very briefly, but I don't see how your auto_ptr can be returned > from functions. Also, why do you need the m_Owner variable? Correct me if I'm wrong, but wasn't there a specific reason why the STL auto_ptr was made so it couldn't be passed to or returned from a function? I don't have my Stroustrup book with me to check. Anyways, if you want to pass or return the pointer to/from a function, just use the .get() or .release() functions. I need the m_Owner variable to tell me if I own the pointer before I delete it. Chris Just __________________________________ Do you Yahoo!? The all-new My Yahoo! - Get yours free! http://my.yahoo.com

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Wave review ends February 19, 2005
by Tom Brinkman 13 Feb '05

13 Feb '05

The boost::wave review ends in six days, February 19, 2005. Please get your review in by then. If you need more time, please contact me personally. Review Manager, Tom Brinkman __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail

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BOOST_PP_SEQ_FOR_EACH_I
by Arkadiy Vertleyb 13 Feb '05

13 Feb '05

Hi all, I don't think that reentrancy mechanism is working for this macro. Is it supposed to? The following example illustrates my problem (I tried both automatic and manual methods): #include <boost/preprocessor/seq/for_each_i.hpp> #define seq\ ((1)(2)(3))\ ((4)(5)(6))\ ((7)(8)(9)) #define MACRO(r, data, i, elem)\ BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, elem) #define MACRO1(r, data, i, elem)\ BOOST_PP_SEQ_FOR_EACH_I_R(r, MACRO2, ~, elem) #define MACRO2(r, data, i, elem)\ elem BOOST_PP_SEQ_FOR_EACH_I(MACRO, ~, seq) BOOST_PP_SEQ_FOR_EACH_I(MACRO1, ~, seq) Both preprocessors I tried, VC71 and GCC 3.4.2, produce the same result: BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, (1)(2)(3) ) BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, (4)(5)(6) ) BOOST_PP_SEQ_FOR_EACH_I(MACRO2, ~, (7)(8)(9) ) BOOST_PP_SEQ_FOR_EACH_I_M(3, (MACRO2, ~, (1)(2)(3) (nil), 0)) BOOST_PP_SEQ_FOR_EACH_I_M(4, (MACRO2, ~, (2)(3) (nil), 1)) BOOST_PP_SEQ_FOR_EACH_I_M(5, (MACRO2, ~, (3) (nil), 2)) BOOST_PP_SEQ_FOR_EACH_I_M(4, (MACRO2, ~, (4)(5)(6) (nil), 0)) BOOST_PP_SEQ_FOR_EACH_I_M(5, (MACRO2, ~, (5)(6) (nil), 1)) BOOST_PP_SEQ_FOR_EACH_I_M(6, (MACRO2, ~, (6) (nil), 2)) BOOST_PP_SEQ_FOR_EACH_I_M(5, (MACRO2, ~, (7)(8)(9) (nil), 0)) BOOST_PP_SEQ_FOR_EACH_I_M(6, (MACRO2, ~, (8)(9) (nil), 1)) BOOST_PP_SEQ_FOR_EACH_I_M(7, (MACRO2, ~, (9) (nil), 2)) Which, I think, indicates that reentrancy is not working. Am I missing something? Regards, Arkadiy

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Querying the Interest in a new AutoPtr class?
by Chris Just 13 Feb '05

13 Feb '05

Hi all, I was wondering what the interest level is for a new auto pointer? I know you've got a few different ones already, but I believe this one has some features that make it quite unique. I based my AutoPtr from the STL auto_ptr and added some additional operator overloads to make it easier to use. The biggest feature however, is that you can specify a custom deletion function object. The custom deletion function object allows you to delete in ways other than just 'delete ptr;' For example, you can delete like this: delete [] ptr; ptr->Delete(); // Delete() calls: delete this; free( ptr ); If you want to take a look at it, it's available at: http://groups.yahoo.com/group/boost/files/AutoPtr/ I'd like to hear your suggestions. Chris Just __________________________________ Do you Yahoo!? Read only the mail you want - Yahoo! Mail SpamGuard. http://promotions.yahoo.com/new_mail

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thread safety in boost intrusive and shared pointers
by Puneet Jain 13 Feb '05

13 Feb '05

I am a new user of boost pointers and was wondering about the thread safety in boost shared and intrusive pointers. After reading some eariler posts and the current documentation, I am little confused. As per current documentation shared pointers thread safety in shared pointers is on the lines of STL and thus they are not thread safe for writing. But I am pretty sure I read in one of the posts that shared pointer is thread safe for all operations. Also, looking at the operator= and swap, it seems there could be some thread safety issues. Also, I have my own counted_base which I use in intrusive pointer. If my understanding is correct, to ensure thread safety, if I ensure add_ref and release_ref operations are atomic, I am pretty much covering all the bases. Thanks, Pete

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[date_time] errors in compiler_config.hpp
by Martin Wille 13 Feb '05

13 Feb '05

Hi, there are several missing logical operators around line 17 of date_time/compiler_config.hpp Regards, m

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