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Composites and Visitors
by Dave Handley 23 Jan '05

23 Jan '05

Following on from a post I made about a week ago regarding a templatised composite, a version of an acyclic visitor, and a version of this visitor designed to visit composite trees, I have uploaded these files to the boost sandbox in a file called composite_visitor.zip. I have included some basic instructions on how to use the classes. I would appreciate some feedback on whether there would be any interest in submitting these for inclusion in Boost. Also I would be interested in any thoughts regarding potential improvements to the templates. Thanks Dave Handley

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Re: [boost] [multi-index] partial_std_allocator_wrapper constructor
by JOAQUIN LOPEZ MU?Z 22 Jan '05

22 Jan '05

----- Mensaje original ----- De: Daniel James <daniel(a)calamity.org.uk> Fecha: Sábado, Enero 22, 2005 7:08 pm Asunto: [boost] [multi-index] partial_std_allocator_wrapper constructor > Hi, > > I'm using the multi-index allocator utilities for the unordered > associative containers implementation. Because > partial_std_allocator_wrapper can't be constructed from the > standard > allocator, I get an error when I use a standard allocator as a > constructor parameter. I believe it also prevents this with the > multi-index library. > > Would it be possible to apply the attached patch to fix this? (Or > is > there another way?) Umm... Seems you're right. Give me a couple of days (I don't have write CVS access now) and I'll check your fix in. Thanks for the contribution, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Linker errors with basic_string
by Andreas Löffler 22 Jan '05

22 Jan '05

Hi there, I'm getting linker errors when I'm trying to compile my application with VS.2003 and boost-1.32. The application uses a DLL which doesn't use parts of the STL or boost, only the application itself and a static library (which contains the major parts of the code) are using boost, STL and MFC code. mfcie error LNK2019: Nicht aufgelöstes externes Symbol '"class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@ABV?$basic_str ing@DU?$char_traits@D@std@@V?$allocator@D@2@@0@@Z)', verwiesen in Funktion '"public: class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall MemoryInfo::getTotalRam(void)const " (?getTotalRam@MemoryInfo@@QBE?AV?$basic_string@DU?$char_traits@D@std@@V?$all ocator@D@2@@std@@XZ)' mfcie error LNK2001: Nichtaufgelöstes externes Symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@ABV?$basic_str ing@DU?$char_traits@D@std@@V?$allocator@D@2@@0@@Z) mfcie error LNK2001: Nichtaufgelöstes externes Symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@ABV?$basic_str ing@DU?$char_traits@D@std@@V?$allocator@D@2@@0@@Z) mfcie error LNK2019: Nicht aufgelöstes externes Symbol '"__declspec(dllimport) class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,char const *)" (__imp_??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@PBD@Z)', verwiesen in Funktion '"public: virtual void __thiscall DriveInfo::determineDriveInfo(unsigned int const &)" (?determineDriveInfo@DriveInfo@@UAEXABI@Z)' mfcie error LNK2001: Nichtaufgelöstes externes Symbol "__declspec(dllimport) class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,char const *)" (__imp_??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@PBD@Z) mfcie error LNK2019: Nicht aufgelöstes externes Symbol '"__declspec(dllimport) class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,char const *)" (__imp_??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@PBD@Z)', verwiesen in Funktion '"protected: virtual void __thiscall OSInfo::determineOSInfo(void)" (?determineOSInfo@OSInfo@@MAEXXZ)' mfcie error LNK2001: Nichtaufgelöstes externes Symbol "__declspec(dllimport) class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,char const *)" (__imp_??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@PBD@Z) mfcie error LNK2019: Nicht aufgelöstes externes Symbol '"__declspec(dllimport) class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl std::operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,char)" (__imp_??6std@@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@0@AAV10@D@Z)', verwiesen in Funktion '"public: virtual void __thiscall DriveInfo::determineDriveInfo(unsigned int const &)" (?determineDriveInfo@DriveInfo@@UAEXABI@Z)' mfcie error LNK2019: Nicht aufgelöstes externes Symbol '"__declspec(dllimport) bool __cdecl std::operator==(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (__imp_??8std@@YA_NABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2 @@0@0@Z)', verwiesen in Funktion '"public: enum CpuStats::e_CPUVENDORS __thiscall CpuStats::getVendor(void)const " (?getVendor@CpuStats@@QBE?AW4e_CPUVENDORS@1@XZ)' mfcie fatal error LNK1120: 4 unaufgelöste externe Verweise Any ideas? Greetings Andrew

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null
by Jason Hise 22 Jan '05

22 Jan '05

Just wondering if there was any interest in a better null, or if such a thing existed in boost already. The code is relatively simple: class null { public: explicit null ( void * ) { } ~ null ( ) { } template < typename T > operator T * ( ) { return 0; } }; null null ( 0 ); Example usage: int * p = null; // ok int i = null; // error: null cannot be converted to an int -Jason

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shared_ptr<> vast questions
by Dave 22 Jan '05

22 Jan '05

Hello NG, With regard to shared_ptr<>... Let's say I have a heap object of type O that contains one subobject of type SO. At this point, I'm deliberately not saying whether the subobject is brought into the object by public inheritance or by containment. Either way, the memory layout is the same under most implementations. May I upcast shared_ptr<O> to shared_ptr<SO> in any case? Or, does the answer depend on whether the subobject has been brought in by public inheritance or by containment? Same question for a downcast (dynamic cast)... Thanks, Dave

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Re: [boost] Re: [multi_index] interest in a random-access index?
by JOAQUIN LOPEZ MU?Z 21 Jan '05

21 Jan '05

Hi Jeff, ----- Mensaje original ----- De: Jeff Flinn <TriumphSprint2000(a)hotmail.com> Fecha: Viernes, Enero 21, 2005 4:46 pm Asunto: [boost] Re: [multi_index] interest in a random-access index? > Joaquín Mª López Muñoz wrote: > > A. Is there interest in having this in Boost.MultiIndex? I wouldn't > > like to add stuff just for the fun of it. > > Definitely! I've been thinking about replacing the internals of a > displayTable class that is derived from the MFC ListView class. I > need random > access when the user does in place editing, while also needing to > allowordering by multiple indices when the user clicks on a column > header. I've taken a look at CListCtrl and cannot figure out why you need a randon-access index (the additional ordered indices seem obvious enough.) Just to make sure, would you care to explain how a random-access index would be used in your situation? (thanks) In case I finally write this, would you volunteer to test a beta version of it to assess its usefulness? Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[multi_index] interest in a random-access index?
by Joaquín Mª López Muñoz 21 Jan '05

21 Jan '05

Hello, I'm considering the possibility of devising a new type of index for Boost.MultiIndex with random-access capabilities, modeled pretty much after the interface of std::vector (with some significant pros and cons.) The basic features of such an index would be: 1. Traversal order is set by the user as with sequenced types. A vector-like insertion interface is provided (push_back/front, positional insert). 2. Iterators are random-access. The index provides an operator[]/at() interace. Advancing/incrementing an iterator involves internally an addition and two pointer dereferences: not as fast as a real vector, but very fast indeed. 3. The memory overhead is two pointers per element. 4. Iterators and references are stable, i.e. they remain valid on the face of insertions/deletions (std::vector does not guarantee this.) 5. Memory storage is *not* contiguous: so, (&begin[0])+n cannot be used to sequentally access all the elements of the index, unlike std::vector. 6. The complexity bounds are much the same as those of a vector: amortized constant insertion/deletion at the end, linear otherwise. My questions are: A. Is there interest in having this in Boost.MultiIndex? I wouldn't like to add stuff just for the fun of it. B. Any suggestion for the name of such an index? Thank you, Joaquín M López Muñoz Telefónica, Investigación y Desarrollo

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[filesystem] Now uses POSIX readdir_r if available
by Beman Dawes 21 Jan '05

21 Jan '05

CVS has been updated: * For POSIX systems, directory_iterator now uses readdir_r if available, with a fallback to readdir otherwise. The POSIX readdir function uses a static buffer, so is unsafe in multi-threaded apps. Furthermore, there has been a report that readdir on Mac OS X does not meet the POSIX requirement of a different static buffer for each directory stream; readdir_r should solve that problem too. * Tests have been added to operations_test.cpp to detect interference between directory_iterators. The changes have been tested using operations_test.cpp on Red Hat Linux 8.0 and Windows XP. Since gcc on this Linux does supply readdir_r, the code was tweaked by hand to force use of readdir. Both passed. Please let me know right away if you run into any problems! --Beman

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about the Data_time; How I can init a ptime that only have the time no the date;
by "帅哥:->代小飞" 21 Jan '05

21 Jan '05

As I knew : construct a ptime use the ptime("2002-01-20 23:59:59.000"); but now I want to init a ptime look like ptime("23:59:59.000");when I use this funcation,a exception is show! any body can tell me ,,How Can i do?!

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Borland and ADL
by Gennadiy Rozental 21 Jan '05

21 Jan '05

Why Borland config doesn't have BOOST_NO_ARGUMENT_DEPENDENT_LOOKUP defined? In my experience it doesn't ADL at least up to 5.6.4 (when I tried) Gennadiy

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