November 2013 - Boost - lists.boost.org

A GUI Library
by jinhao 09 Nov '17

09 Nov '17

Hi, all I am developing a GUI library, it takes aim at easy-to-use and portable library for modern C++ methods. The project at http://stdex.sourceforge.net A git repository at http://nanapro.codeplex.com A brief at http://nanaproject.wordpress.com/2011/12/16/preliminary-study-of-nana-c-lib… Is there any interest in this library? Regards Jinhao

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bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

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[context] msvc /SAFESEH
by Jeff Flinn 12 Aug '15

12 Aug '15

I need to build my application with /SAFESEH which uses boost coroutine which uses context. I'm getting the following link errors: 1>libboost_context-vc100-mt-gd-1_53.lib(jump_i386_ms_pe_masm.obj) : error LNK2026: module unsafe for SAFESEH image. 1>libboost_context-vc100-mt-gd-1_53.lib(make_i386_ms_pe_masm.obj) : error LNK2026: module unsafe for SAFESEH image. I've built boost static libs with the same MSVC vesion and options (sans /SAFESEH as it's not a compile/lib option) Compiler/linker versions: Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.40219.01 for 80x86 Microsoft (R) Incremental Linker Version 10.00.40219.01 Has anyone run into this and resolved the error? Any insight is appreciated. Thanks, Jeff

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Arguing about names in Boost libraries
by Edward Diener 07 May '15

07 May '15

What is wrong with the people commenting on libraries for Boost who are so concerned about the names being used ? We are talking only about C++ identifiers and yet there are now endless discussions where people disagree on names or argue that some name is not what they want or that they like some other name, with a list of names that they find adequate. This is irrelevant. There is something mentally wrong about all those peoples spending endless amounts of time around this issue. I notice this does not happen nowadays for just one library but for ever single library, or proposed library, which is mentioned on this mailing list. Is this the way all of you people actually work in your daily jobs, or on your own projects, spending hours and days arguing with others about C++ identifiers for every little thing ? Are you not aware of the absurdity of your endless remarks ? Grow up ! Surely there are better things to do than carry on endlessly about some name, that is should be x or y or z or some other inane preferable list. It's time for somebody to say this, so I will do it. A C++ identifier name, as long as it is vaguely about what the functionality entails, is perfectly adequate. It does not have to satisfy everyone in the universe. Period !

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IDE for developing Boost
by Jens Müller 20 Dec '14

20 Dec '14

Hi, I am looking for recommendations for developing Boost, especially code in the graph library. At work, most developers (not for Boost, for some commercial software), most developers are using Eclipse. This works quite fine as soon as it has properly auto-discovered include paths etc. But before fiddling around with Eclipse to get all the settings right, I'd wanted to to ask for your recommendations. And maybe there are already settings available to make it "just work", at least initially. Cheers, Jens

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Is there any interest in a library for actor programming?
by Charousset, Dominik 28 May '14

28 May '14

Hi, is there any interest in a library for actor programming? The library we've developed is a C++11 open source library named "libcppa". It is currently released under LGPL2, but re-releasing the library under the boost license is not an issue. You'll find all important links and ressources either under http://libcppa.org or on the GitHub project page: https://github.com/Neverlord/libcppa, including a user manual as HTML or PDF. We've also submitted a paper to the C++Now conference. What is actor programming? For those of you who aren't yet familiar with the actor model: actors basically represent tasks or services that communicate via message passing. In libcppa, actors are very lightweight (you can spawn literally millions of them) and scheduled cooperatively using a thread pool (although actors are allowed to opt-out of the cooperative scheduling). Some of the main strengths of this programming paradigm are: (1) network transparency, (2) race conditions are avoided by design, (3) a strong failure model that enables developers to build reliable distributed systems, and (4) the actor model addresses both concurrency (multiple actors on one host) and distribution (any number of actors on any number of hosts). Here's the classical hello world example: ---------------------------------------------------------------------------------- #include <string> #include <iostream> #include "cppa/cppa.hpp" using namespace std; using namespace cppa; void mirror() { // wait for messages become ( // invoke this lambda expression if we receive a string on_arg_match >> [](const string& what) { // prints "Hello World!" via aout (thread-safe cout wrapper) aout << what << endl; // replies "!dlroW olleH" reply(string(what.rbegin(), what.rend())); // terminates this actor ('become' otherwise loops forever) self->quit(); } ); } void hello_world(const actor_ptr& buddy) { // send "Hello World!" to our buddy ... sync_send(buddy, "Hello World!").then( // ... and wait for a response on_arg_match >> [](const string& what) { // prints "!dlroW olleH" aout << what << endl; } ); } int main() { // create a new actor that calls 'mirror()' auto mirror_actor = spawn(mirror); // create another actor that calls 'hello_world(mirror_actor)' spawn(hello_world, mirror_actor); // wait until all other actors we have spawned are done await_all_others_done(); // run cleanup code before exiting main shutdown(); } ---------------------------------------------------------------------------------- A message is simply a tuple of values that is pattern matched at the receiver. For example, " on_arg_match >> [](const string& what) {...}" defines a message handler that is called whenever a tuple with one single string element arrives. "on_arg_match" simply defines a pattern that matches the signature of the given lambda. Please have a look at the examples folder on GitHub (https://github.com/Neverlord/libcppa/tree/master/examples) or at the user manual (http://neverlord.github.io/libcppa/manual/) if you want to see more examples. Best regards, Dominik Charousset

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required toolsets
by Steven Watanabe 15 May '14

15 May '14

AMDG The list of required toolsets in explicit-failures-markup.xml is out-dated. Therefore, if no one objects, I propose setting it to the following: msvc-10.0, msvc-11.0, gcc-4.6, gcc-4.7, clang-darwin-11, clang-darwin-4.2.1, clang-linux-3.1, clang-linux-3.2, gcc-mingw-4.7, gcc-mingw-4.6 (two releases of each major compiler that appears in both the trunk and release regression tests) The sole effect of this is to determine which toolsets appear in the issues list: http://www.boost.org/development/tests/trunk/developer/issues.html In Christ, Steven Watanabe

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[atomic] Support for specialized instructions
by Andrey Semashev 14 May '14

14 May '14

Hi, I've been contemplating the idea of adding support for some specialized atomic instructions to Boost.Atomic. Since I'm only familiar with x86 architecture, my current candidates are: * Increment/decrement with a check for zero result (lock inc/dec). The decrement is the most essential of the two because it would be useful for reference counters of various kinds. The increment is mostly beneficial in terms of code size, and it probably doesn't need the check for zero in most cases. * In-place logical operations (lock and/or/xor). These are useful in cases when the code needs to operate on flags or bit sets but doesn't need the result of the operation. Optional variants can be provided with a test for zero result. * Bit set/reset operations (lock bts/btr). The use cases are similar to the logical operations but the advantage is that the previous value of the altered bit can be returned. BTW, these operations are needed in Boost.Sync to implement mutexes on Windows. All these operations can be implemented through the standard atomic<> interface, and that's what would be done on platforms without support for the specialized instructions. For now the idea is to add special member functions to atomic<>, when used with arithmetic types. I was thinking about providing free functions as well, although I think that the complete set of the standard atomic functions would be required for that. Comments? Opinions?

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Why no non-null smart pointers?
by Ross MacGregor 29 Apr '14

29 Apr '14

I just created a very small smart pointer libary for our project. It will contain two types of shared pointers: SharedHandle and NullableSharedHandle. SharedHandle will be a shared pointer that cannot be null by ensuring a non-null construction while NullableSharedHandle will basically be a typedef for boost::shared_ptr. I firmly believe that code can be made more reliable by minimizing the use of nullable pointers. To this end, I think it is important that we start using non-null pointer types. Ideally the compiler would be able to understand a non-null pointer and catch bugs at compile time, but I think we can still improve things with a few runtime checks. If we make sure that a shared pointer is constructed with a non-null pointer and ban any reset() type methods, we guarentee that it points to something. This can be beneficial for the following reasons: 1. Any function that uses this type will no longer be burdened with precondition checks to make sure variables of this type are not null. 2. It's type is simply more explicit and better explains its function. 3. Moving the non-null check to the creation phase will reduce the possibility of encountering null pointer exceptions at runtime (assuming there are many more pointer references than constructor calls). So my little pointer library seems to make a lot of sense, but if so why hasn't this simple smart pointer variation made it into boost yet? Has this been discussed somewhere already? My search on non-null smart pointers is not revealing much discussion on the topic. Regards, Ross

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boost::optional -- updates for C++11 move semantics
by Diggory Hardy 10 Apr '14

10 Apr '14

Dear list, I wanted something like boost::optional, but with support for move- construction/assignment, so I went ahead and had a go at patching it. Attached is based on boost 1.49 (Ubuntu package). Could someone please review? I've not contributed to boost before. The changes at least aren't too complicated, but: 1) I'm not entirely sure if the move constructor (line 636) and swap function (line 1046) are implemented in the best way (also see line 279), 2) and I have no idea how is_[not_]reference_tag (line 486) works. 3) There should maybe also be a unit test. Of course, I am happy for my contributions to be published under the boost licence. Regards, Diggory

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