November 2015 - Boost - lists.preview.boost.org

Re: [boost] Boost CRC maintainer (Daryle Walker) missing in action?
by Olaf van der Spek 19 Jun '17

19 Jun '17

Hi Daryle, Any luck on your new setup? Gr, Olaf On Mon, Nov 28, 2011 at 1:11 AM, Daryle Walker <darylew(a)gmail.com> wrote: > I can look at it once I've finished my new setup. > > I had to reset my computer after a partial crash years ago. I never > got around to recreating my programming setup. My computer had been > at its maximum Operating System level back then, which is now 3 > versions behind. For the past few months, I've had my sister's old > laptop, with Windows Vista, and am trying to add a programming setup > to it now. > > > On Tue, Nov 22, 2011 at 7:18 AM, Beman Dawes <bdawes(a)acm.org> wrote: >> Hi Daryle, >> >> This guy has volunteered to take over maintenance of Boost CRC. Should >> we take him up on his offer? > >> ---------- Forwarded message ---------- >> From: >> Date: Wed, Nov 2, 2011 at 7:51 AM >> Subject: [boost] Boost CRC maintainer (Daryle Walker) missing in action? >> To: boost(a)lists.boost.org >> >> >> Hi, >> >> It looks like the Boost CRC maintainer (Daryle Walker) is missing in action? >> >> No response to tickets from the past 3 years. What's the procedure in this case? >> >> https://svn.boost.org/trac/boost/ticket/2492 >> https://svn.boost.org/trac/boost/query?component=crc&col=id&col=summary&col… > > -- > Daryle Walker > Mac, Internet, and Video Game Junkie > darylew AT gmail DOT com -- Olaf

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[container] moving a pre-built vector into a flat_set
by Sam Kellett 12 Mar '17

12 Mar '17

a common problem i encounter is that i have two stage's w/r/t to a large collection of data: building and querying. vector is obviously the king of building. flat_set is the king of querying. so what i often tend to do is build up a very large vector, sort it then create a flat_set using the flat_set(ordered_unique_t) constructor. however this still copies the entire vector into the flat_set, right? what i would like to be able to do is move the vector straight into the flat_set, something like: std::vector<T> data; flat_set data_set1(std::move(data)) // move vector in and sort it // or: std::sort(data.begin(), data.end()); // sort vector flat_set data_set2(ordered_unique_t, std::move(data)) // and move it in is this doable (am i just being blind?) or is there plans/interest for this?

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[config] RFC PR 82
by Domagoj Saric 01 Aug '16

01 Aug '16

Hi everyone, I am finally getting back to (trying to) contributing some of my personal projects to Boost. For two of those, Err (https://github.com/psiha/err) and especially Functonoid (a C++11 generalization and rewrite of my previous Boost.Function related work) I need some lower level codegen and/or optimiser control functionality (i.e. portable macros wrapping toolset specific attributes and pragmas) that I've added to my personal fork of Boost.Config and which I've now submitted in the subject PR (https://github.com/boostorg/config/pull/82). I don't expect this PR to be accepted as is/'just like that' so I'm opening this thread where we can discuss which of those changes/macros are welcome, which need more work and which, for some reason, should not be part of Boost.Config (and which, in turn then, I have to move to some 'internal implementation headers' in libraries that will need them). To avoid 'spamming' (and save time;) I'll skip the explanation of the individual macros as I expect them to mostly be self-explanatory (if not from their name then from the minimal Boost.Config documentation additions that are part of th PR). ps. I'll be on the (off) road for the next three weeks so I don't know when I'll be able to respond until I get back... -- "What Huxley teaches is that in the age of advanced technology, spiritual devastation is more likely to come from an enemy with a smiling face than from one whose countenance exudes suspicion and hate." Neil Postman

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[Fit] pipable order of the arguments
by Vicente J. Botet Escriba 05 Mar '16

05 Mar '16

Hi, I would like to know what other think about the order of the pipe (See this issue https://github.com/pfultz2/Fit/issues/5). What would be the expected meaning of auto r1 =1 | pipable(f)(2); f(1,2) or f(2,1)? What would be the expected meaning of auto f2 = partial(f)(2); auto r1 =1 | pipable(f2); f(1,2) or f(2,1)? As the operator| has left-to-right associativity, we can not do auto x = 1 | 2 | pipable(f); We would need a way to pack the parameters auto x = forward_as_tuple(1, 2) | pipable(f); but this wouldn't compile as f has two parameters. or use parenthesis auto x = 1 | (2 | pipable(f)); and the result will be f(2, 1). Any ideas? Best, Vicente Vicente

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[regression] Winapi submodule tests missing
by Andrey Semashev 13 Feb '16

13 Feb '16

Hi, The winapi submodule tests are missing from the test matrix, although the status/Jamfile.v2 lists it. This is both on develop and master. Is there something I should do to make the tests appear?

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[err] RFC
by Domagoj Saric 11 Jan '16

11 Jan '16

https://github.com/psiha/err README.md copy-paste: --------------------------------------------- err - yet another take on C++ error handling. We have throw and std::error_code, what more could one possibly want? --------------------------------------------- std::error_code&co tried to solve or at least alleviate the problem of overhead of using exceptions (in terms of both source code verbosity and binary code size&speed) with functions which need to report failures that need not be 'exceptional' depending on the context of the call (thereby requiring try-catch blocks that convert exceptions to 'result codes'). Unfortunately, the way it was finally implemented, std::error_code did not quite accomplish what it set out to do: • in terms of runtime efficiency: 'manual'/explicit EH (try-catch blocks) is no longer needed but the compiler still has to insert hidden EH as it has to treat the functions in question as still possibly throwing (in fact the implementation/codegen of functions which use std::error_code for error reporting becomes even fatter because it has to contain both return-on-error paths and handle exceptions) • in terms of source code verbosity: again, try-catch blocks are gone but separate error_code objects have to be declared and passed to the desired function. Enter boost::err: 'result objects' (as opposed to just result or error codes) which can be examined and branched upon (like with traditional result codes) or left unexamined to self-throw if they contain a failure result (i.e. unlike traditional result codes, they cannot be accidentally ignored). Thanks to latest C++ language features (such as r-value member function overloads) incorrect usage (that could otherwise for example lead to a result object destructor throwing during a stack-unwind) can be disallowed/detected at compile time. Discussions where the concept (or a similar one) was first concieved of and/or so far discussed: • http://boost.2283326.n4.nabble.com/system-filesystem-v3-Question-about-erro… • http://cpptips.com/fallible • https://github.com/ptal/std-expected-proposal • https://github.com/ptal/expected • https://github.com/adityaramesh/ccbase/blob/master/include/ccbase/error/exp… • http://stackoverflow.com/questions/14923346/how-would-you-use-alexandrescus… • https://svn.boost.org/trac/boost/wiki/BestPracticeHandbook#a8.DESIGN:Strong… • http://2013.cppnow.org/session/non-allocating-stdfuturepromise **************************************************************** For starter's, to reduce the length of the first post, I'll assume that everyone as at least somewhat familiar with similar/related proposals from Andrei Alexandrescu (std::expected) and Niall Douglas (std::monad) to which I gave links above. What, primarily, makes (Boost.)Err different from other proposals is the ability to (using latest C++ features) detect/distinguish between temporaries and 'saved' return values by using two different class templates (result wrappers), fallible_result (for rvalues) and result_or_error (for lvalues) and thus minimise or often completely eliminate any extra verbosity: If we had a function foo() that produces bar_t objects but can fail with an err_t, up till now we had two options: * bar_t foo() throw( err_t ); * optional<bar_t> foo( err_t & ); Err enables the library writer to write a single API and a single implementation: err::fallible_result<bar_t, err_t> foo(); where fallible_result is the class template that wraps temporaries/rvalues returned from functions and its member functions are all declared with && (i.e. callable only on rvalues) so you get a compiler error if you save it to an auto value and try to do anything with it. The two exceptions are the implicit conversion operators to: - bar_t, which will either return bar_t or throw err_t and which is used for the 'EH code path' bar_t my_bar( foo() ); - err::result_or_error<bar_t, err_t> which is used for the 'oldsk00l nothrow error code path' err::result_or_error<bar_t, err_t> maybe_bar( foo ); if ( maybe_bar ) { print( *maybe_bar ); } else { log( maybe_bar.error() ); } Also, if the fallible_result rvalue is left uninspected and contains an error its destructor will throw (which AFAICT should be safe considering it is an rvalue and no other exception can possibly be active at the same time) - this makes code that uses Err enabled libraries/APIs but relies on EH almost indistinguishable from 'classic EH' APIs (almost because the one difference that remains is with the immediate use of the return value: because of the wrapper class one can no longer write foo().do_something() but has to implicitly use the -> operator and write foo()->do_something() where the -> operator will check-and-throw if foo() did not succeed). To wrap up, this approach gives the user the immediate and fine grained control over which error handling mechanism he/she wants to use while allowing the developer to write a single API and implementation - AFAICT it is a no brainer replacement for <system_error>, it is less verbose and much more efficient ;-) ps. the small library @ https://github.com/psiha/err is by no means a finished product, it contains no tests or documentation but 'it works' (i.e. it is used in the, also upcoming, https://github.com/psiha/mmap)...I'm bringing it to public view for scrutiny, discussion and guidance lest I steer in the wrong direction ;) -- "What Huxley teaches is that in the age of advanced technology, spiritual devastation is more likely to come from an enemy with a smiling face than from one whose countenance exudes suspicion and hate." Neil Postman

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Problems building Boost libraries for Windows Store when C++/CX is involved
by Mikael Olenfalk 04 Jan '16

04 Jan '16

Hi, I am working on porting the boost libraries we depend on to winrt, most porting is rather straightforward (basically switch from win32 apis which are 20 years old to apis which are 15 years old :D ). However I have hit a bit of a problem when compiling Boost.Log. Boost.Log depends on Boost.Asio which uses C++/CX to call some of the newer Store APIs (Windows::Networking and friends). When I build I get these errors: compile-c-c++ ..\..\..\bin.v2\libs\log\build\msvc-14.0\debug\log-api-winnt\threading-multi\windows-api-store\dump_ssse3.obj dump_ssse3.cpp ..\..\..\libs\log\src\dump_ssse3.cpp: fatal error C1107: could not find assembly 'platform.winmd': please specify the assembly search path using /AI or by setting the LIBPATH environment variable call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 store >nul cl /Zm800 /ZW /EHsc -nologo @"..\..\..\bin.v2\libs\log\build\msvc-14.0\debug\log-api-winnt\threading-multi\windows-api-store\dump_ssse3.obj.rsp" (As you can see I have monkey-patched msvc.jam to append the "store" argument to vcvarsall.bat - to no avail :( -- the monkey-patch is here if you want to look at it: https://github.com/mauve/build/commits/universal-windows-boost-1.59.0 ) The @response file looks like this: "..\..\..\libs\log\src\dump_ssse3.cpp" -Fo"..\..\..\bin.v2\libs\log\build\msvc-14.0\debug\log-api-winnt\threading-multi\windows-api-store\dump_ssse3.obj" -TP /Z7 /Od /Ob0 /W3 /GR /MDd /Zc:forScope /Zc:wchar_t /wd4675 /EHs /arch:SSE2 /bigobj /wd4003 /wd4456 /wd4459 /wd4503 -c -DBOOST_ALL_NO_LIB=1 -DBOOST_CHRONO_DYN_LINK=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_LOG_BUILDING_THE_LIB=1 -DBOOST_LOG_DLL -DBOOST_SPIRIT_USE_PHOENIX_V3=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRECATED -DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_DONT_USE_CHRONO=1 -DBOOST_THREAD_USE_DLL=1 -DDATE_TIME_INLINE -DWINAPI_FAMILY=WINAPI_FAMILY_APP -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_WIN32_WINNT=0x0603 "-I..\..\.." Regards, Mikael

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[multiprecision] uses boost::math::gcd without including the header
by Peter Dimov 04 Jan '16

04 Jan '16

include/boost/multiprecision/cpp_int/misc.hpp uses boost::math::gcd (and lcm), but does not include common_factor_rt.hpp.

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Status of the CMake-ification
by Louis Dionne 02 Jan '16

02 Jan '16

Dear Boost, I'd like to inquire about the status of the CMake-ification of Boost that had been started a while ago. AFAICT, the effort is completely stopped now; is this correct? Also, I'd like to poll the community to gauge interest in the rebirth of such an effort. __I'm not proposing myself to work on such a rebirth__, but I'm just curious to know what the community thinks about it. I, for one, would love to see it happen. Regards, Louis -- View this message in context: http://boost.2283326.n4.nabble.com/Status-of-the-CMake-ification-tp4681599.… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[smart_ptr] Moving cast for unique_ptr
by Karolin Varner 21 Dec '15

21 Dec '15

Hi all! There is the family of boost pointer cast (boost::static_pointer_cast, boost::dynamic_pointer_cast, ...) that allow a developer to write generic code by casting pointers regardless of whether they are some smart pointer (e.g. shared_ptr) or plain pointers. However, those functions have not been implemented for unique_ptr, because they create a copy of their pointer and unique_pointers can not be copied. In my case I still needed to cast some unique_ptr and since it's ok to move unique_ptrs I wrote a function that does exactly that. The code is below – Comments are very, very welcome. It works for my case, but I am sure it is not as generic and safe as it should be ;) . Specifically, for a library, it should be made to work on any kind of smart/plain pointer. Not just unique_ptr. Is there any interest to include a boost::static_moving_pointer_cast and the other types of casts in boost? Best, Karolin /// Dynamic cast a unique_ptr. /// /// This function shall move the pointer in in_ptr, into /// a new unique_pointer of the desire type, dynamic_casting /// it in the process. /// In given pointer shall contain a NULL pointer afterwards. /// /// If unsuccessful, function shall throw an error and leave /// in_ptr unmodified. /// /// This behaviour contrasts a bit with the behaviour of the /// normal dynamic_cast: /// 1. dynamic_cast copies objects, this moves them since /// unique_pointers can not be copied. /// 2. dynamic_cast returns a NULL pointer if the pointer to /// cast is of an incomplete type, this throws /// incomplete_cast instead, to ease error handling. /// /// @tparam T The type to convert to (as non-pointer) /// @tparam F The type to convert from (as non-pointer) /// @param in_ptr The unique_ptr to cast /// @return in_ptr, cast to the desired type template<typename T, typename F> std::unique_ptr<T> dynamic_moving_pointer_cast(std::unique_ptr<F> &in_ptr) { // Exception safety: If The dynamic cast throws an error, // or of we throw incomplete_cast, in_ptr will still be // unmodified T *plain_out_ptr = dynamic_cast<F*>(in_ptr.get()); if (plain_out_ptr == NULL && in_ptr.get() != NULL) throw incomplete_cast(); // Exception safety: Both operations are noexcept in_ptr.release(); return std::unique_ptr<T>(plain_out_ptr); }

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