October 2013 - Boost - lists.preview.boost.org

[1.55][Math] Permission to apply bug fix?
by John Maddock 11 Oct '13

11 Oct '13

Is 1.55 release branch open for bug fixes again? If so I'd like to apply the patch for: https://svn.boost.org/trac/boost/ticket/9183 in https://svn.boost.org/trac/boost/changeset/86205 Many thanks, John.

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Looking for thoughts on a new smart pointer: shared_ptr_nonnull
by Luke Bradford 11 Oct '13

11 Oct '13

Hi, I'm new to this list, so apologies for any oversights or faux pas. I've been finding a lot of use for a type of smart pointer I call shared_ptr_nonnull, which is a variation on shared_ptr which is never allowed to be empty. Specifically: (1) It doesn't have reset() with no arguments, doesn't have a default constructor, and doesn't have implicit conversion to bool (which would always be true.) (2) It throws an exception whenever there's an attempt to make it empty, i.e. in constructors, reset, assignment, and swap. For convenience, it's implicitly convertible to shared_ptr, and I have all of shared_ptr's templated operators implemented with possible combinations of shared_ptr and shared_ptr_nonnull. Usually it can be used just by changing the type of a shared_ptr. We have a lot of shared_ptrs, especially member variables, which are claimed to be "always valid" and this class enforces that, at compile time (1) and runtime (2). Has there been any discussion of something like this? Does anybody have any thoughts, suggestions, criticisms? Who's in charge of the smart pointer library these days? Thanks, Luke

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Review wizards response and Boost reviews
by Edward Diener 11 Oct '13

11 Oct '13

I tried to contact the review wizards via their e-mail addresses to update some information on the Boost Formal Review Schedule page at http://www.boost.org/community/review_schedule.html but have heard nothing in response. I appreciate that they have a hard job to do for which most people would not want the responsibility. But it does seem to me, either by plan or because there appear to be no people willing to act as review managers, that the Boost formal review process has completely bogged down for some time now. Since I am interested in getting my own library reviewed I would like to volunteer to act as a Review Manager for other libraries. I have no particular library in mind but I am pretty knowledgeable and interested in some of the ideas of libraries on the review schedule. I have been a Review Manager for a past library and think I did a pretty good job. At the same time I am looking for a review manager for my Variadic Macro Data library. Unfortunately the link to it on the web page above is wrong. It is now on GitHub at https://github.com/eldiener/variadic_macro_data. Edward Diener

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libs/context/src/asm/make_i386_sysv_elf_gas.S:37: Error: junk at end of line
by Frédéric Bron 11 Oct '13

11 Oct '13

Hello, When building with i686-w64-mingw32 cross compiler, this is what I get: libs/context/src/asm/make_i386_sysv_elf_gas.S: Assembler messages: libs/context/src/asm/make_i386_sysv_elf_gas.S:37: Warning: .type pseudo-op used outside of .def/.endef ignored. libs/context/src/asm/make_i386_sysv_elf_gas.S:37: Error: junk at end of line, first unrecognized character is `m' libs/context/src/asm/make_i386_sysv_elf_gas.S:77: Warning: .size pseudo-op used outside of .def/.endef ignored. libs/context/src/asm/make_i386_sysv_elf_gas.S:77: Error: junk at end of line, first unrecognized character is `m' libs/context/src/asm/make_i386_sysv_elf_gas.S:80: Error: junk at end of line, first unrecognized character is `-' ...failed gcc.compile.asm bin.v2/libs/context/build/gcc-mingw-4.8.1/debug/address-model-32/link-static/target-os-windows/threadapi-win32/threading-multi/asm/make_i386_> What does that mean? Frédéric

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[type_traits] VC++ and vararg function/mmeber functions and varargs
by Edward Diener 10 Oct '13

10 Oct '13

After going back and for with Mr. Lavavej from Microsoft about how VC++ treats functions/member functions which have varargs parameters and calling conventions, I learned that VC++ always treats all these function types as if the calling convention is __cdecl, no matter what the end-user specifies. Therefore attempting to match function and member function types taking varargs, with VC++ and compatibles, by having to specify __cdecl, __fastcall, and __stdcall calling conventions for every function/member function declaration with varargs, is a waste since these are not potential new types being tested by templates but just the same type redeclared. These occur in type_traits/detail files is_mem_fun_pointer_tester.hpp and is_mem_fun_pointer_tester.hpp when BOOST_TT_TEST_MS_FUNC_SIGS ( essentially _MSC_EXTENSIONS) is defined. I would like to remove these redundant declarations from these files. I have made sure that my tests for VC++ pass. I will test Intel C++, if it also emulates VC++ in this way. Can I make the change on trunk to these files once I ascertain that Intel C++ tests with type_traits also pass with this change ? Are there any other VC++ emulation compilers that need to be tested ?

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[BGL] Maximum Weight Matching
by Pablo Madoery 10 Oct '13

10 Oct '13

Hello, We wrote the attached code in c++ using Boost, Blossom V and Guido Shafer Reduction to compute Maximum-Weight-Matching (not necessarily perfect) of a graph. We want to contribute to Boost BGL library. We are not experts in boost BGL library but we think that this code can be improved and used in Boost. We wrote this code becouse we need this algorithm and it wasn't in Boost. Although it is in Lemon Library ( http://lemon.cs.elte.hu/pub/doc/1.2.3/a00537.html) we need other algorithms and functions that are only in Boost. Thank you very much

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Weird Boost 1.55 beta failure on VS2013 RC
by Niall Douglas 10 Oct '13

10 Oct '13

Can someone else confirm that Boost v1.55 beta is not compiling on VS2013 RC? I see lots of this: 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(42): error C2065: 'ReadableIterator' : undeclared identifier 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(42): error C2065: 'Iterator' : undeclared identifier 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(43): error C2448: 'BOOST_concept' : function-style initializer appears to be a function definition 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(43): error C2143: syntax error : missing ';' before ':' 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(43): error C2065: 'Iterator' : undeclared identifier 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(43): error C2923: 'boost::Assignable' : 'Iterator' is not a valid template type argument for parameter 'TT' 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(44): error C2143: syntax error : missing ';' before ',' 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(44): error C2059: syntax error : ',' 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(44): error C2065: 'Iterator' : undeclared identifier 2>G:\TripleGit\boost\boost/iterator/iterator_concepts.hpp(44): error C2923: 'boost::CopyConstructible' : 'Iterator' is not a valid template type argument for parameter 'TT' .... Here is the really weird thing - the macro BOOST_concept appears to not be defined, so if you do a: #ifndef BOOST_concept #error Hello #endif ... you get error Hello. Methinks this is a compiler bug in the RC, but can anyone else confirm? Niall -- Currently unemployed and looking for work. Work Portfolio: http://careers.stackoverflow.com/nialldouglas/

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How to center an element in Boost QuickBook?
by Niall Douglas 10 Oct '13

10 Oct '13

As the documentation for proposed Boost.AFIO comes together for this week's GSoC Milestone 1 (feel free to check it out at https://ci.nedprod.com/job/Boost.AFIO%20Build%20Documentation/Boost.AFIO_Doc umentation/?), a problem has emerged. We'd like a matrix table containing ticks and crosses, and building such a thing in QuickBook is easy. However, we'd also like to center the ticks and crosses in each table cell, otherwise it looks poor. Is there some way I haven't realized of aligning content in Boost QuickBook, or even BoostBook itself? The DocBook documentation suggests one can do a '''<entry align="center">'''__tick__'''</entry>''' (the triple single ticks escape from QuickBook into BoostBook). However unfortunately BoostBook defines CSS which overrides the per-cell alignment :( Thanks in advance for the help. Niall --- Opinions expressed here are my own and do not necessarily represent those of BlackBerry Inc.

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Try out a multi-dimensional adapter class template?
by Daryle Walker 10 Oct '13

10 Oct '13

I added a new class template for my library at <https://github.com/CTMacUser/ArrayMD>. It's called "multiarray," and it's an adapter class like stack and queue. But the new interface is only for accessing elements. Besides the element and container types, the template header for the class takes the number of dimensions. The class uses at, operator [] and operator () to access an element. It has methods to read/write the shape of the array and the priority of each index. There are no methods to change the number of elements stored; you have to either use a fixed-size container or sub-class the multi-array to add methods to change the size. (The container sub-object is protected, like the Standard adapters.) I split the main code into two base class templates, because the code for computing the offset from an index tuple and the code for referencing an element were nearly distinct. This really screws up my attempt at Doxygen comments. Any ideas? Or is my case too complex for what Doxygen's author thought could be handled. Daryle W.

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[tokenizer] Some remarks
by Robert Kawulak 09 Oct '13

09 Oct '13

Hi, I have a few proposals/questions related to boost::tokenizer: - the first template parameter of char_separator and other tokenizer functions could be defaulted to char to save typing and make it consistent with the defaults of tokenizer; - making the constructor of char_separator and other tokenizer functions non-explicit would allow for less verbose construction of a tokenizer; - the docs state that char_delimiters_separator is deprecated in favour of char_separator. Are there any plans to actually drop the former and change the default for the template parameter of tokenizer to the latter? I guess this might be controversial because interfaces and semantics of the two differ, so maybe providing a new template, say string_tokenizer, is a good idea? Combining the first two points, the following: auto t = boost::tokenizer<boost::char_separator<char>>( str, boost::char_separator<char>("-;|")); could be written more conveniently as: auto t = boost::tokenizer<boost::char_separator<>>(str, "-;|"); and adding the third point it would become: auto t = boost::string_tokenizer<>(str, "-;|"); which is IMO a significant improvement. Any thoughts? Best regards, Robert

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