C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  C++0x container constructors for DefaultConstructible object          C++Talk.NET Forum Index -> C++ language, library and standards View previous topic :: View next topic   Author Message Bo Persson Guest Posted: Mon May 21, 2007 7:04 am    Post subject: C++0x container constructors for DefaultConstructible object I notice in the draft N2284 that sequence containers have had one constructor split in two. We now have (for list<T>): explicit list(size_type n); list(size_type n, const T& value, const Allocator& = Allocator()); How come the first type of constructor doesn't take an allocator parameter? Bo Persson --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ] Back to top Howard Hinnant Guest Posted: Mon May 21, 2007 8:59 pm    Post subject: Re: C++0x container constructors for DefaultConstructible ob In article <5b91g3F2rt1iiU1 (AT) mid (DOT) individual.net>, bop (AT) gmb (DOT) dk ("Bo Persson") wrote: Quote: I notice in the draft N2284 that sequence containers have had one constructor split in two. We now have (for list<T>): explicit list(size_type n); list(size_type n, const T& value, const Allocator& = Allocator()); How come the first type of constructor doesn't take an allocator parameter? Mainly just history. People have never been able to say: std::list<T, A> c(n, A()); And I've never heard any requests for that functionality. So I didn't add it. It easily could be added. Is there demand for it? Would you be willing to write a short paper or defect report with detailed proposed wording relative to N2284? -Howard --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ] Back to top Bo Persson Guest Posted: Tue May 22, 2007 3:44 am    Post subject: Re: C++0x container constructors for DefaultConstructible ob Howard Hinnant wrote: :: In article <5b91g3F2rt1iiU1 (AT) mid (DOT) individual.net>, :: bop (AT) gmb (DOT) dk ("Bo Persson") wrote: :: ::: I notice in the draft N2284 that sequence containers have had one ::: constructor split in two. We now have (for list<T>): ::: ::: explicit list(size_type n); ::: list(size_type n, const T& value, const Allocator& = Allocator()); ::: ::: How come the first type of constructor doesn't take an allocator ::: parameter? :: :: Mainly just history. People have never been able to say: :: :: std::list<T, A> c(n, A()); :: :: And I've never heard any requests for that functionality. So I :: didn't add it. It easily could be added. Is there demand for it? :: Would you be willing to write a short paper or defect report with :: detailed proposed wording relative to N2284? :: I was really just curious about why one constructor breaks the pattern. Having already written a defect report for for strings (#614), I noticed that other containers now also deviate from the container requirements in 23.1/9, where it says that constructors should all take an Allocator& argument. Except when they don't? I can also guess that the new constructor should default construct the container's allocator member, but haven't found that it says so anywhere. Did I miss this requirement, or is it just obvious anyway? Bo Persson --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. If that fails, use mailto:std-c++@ncar.ucar.edu ] [ --- Please see the FAQ before posting. --- ] [ FAQ: http://www.comeaucomputing.com/csc/faq.html ] Back to top Pete Becker Guest Posted: Tue May 22, 2007 3:45 am    Post subject: Re: C++0x container constructors for DefaultConstructible ob Howard Hinnant wrote: Quote: In article <5b91g3F2rt1iiU1 (AT) mid (DOT) individual.net>, bop (AT) gmb (DOT) dk ("Bo Persson") wrote: I notice in the draft N2284 that sequence containers have had one constructor split in two. We now have (for list<T>): explicit list(size_type n); list(size_type n, const T& value, const Allocator& = Allocator()); How come the first type of constructor doesn't take an allocator parameter? Mainly just history. People have never been able to say: std::list<T, A> c(n, A()); And I've never heard any requests for that functionality. So I didn't add it. It easily could be added. Is there demand for it? Would you be willing to write a short paper or defect report with detailed proposed wording relative to N2284? Please, not a "defect report." Defect reports apply only to published standards, and they invoke a formal response process. -- -- Pete Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The Standard C++ Library Extensions: a Tutorial and Reference." (www.petebecker.com/tr1book) --- [ comp.std.c++ is moderated. To submit articles, try just posting with ] [ your news-reader. 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