June 2016 - Boost - lists.preview.boost.org

[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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[contract] Without the macros
by Lorenzo Caminiti 19 Jul '16

19 Jul '16

Hello all, In the last few years my professional and personal lives changed quite a bit limiting my ability to contribute to Boost. However, in my spare time I slowing continued to revise Boost.Contract hoping to be able to commit it to a Boost release someday (after the library was accepted 3+ years ago... https://groups.google.com/forum/?fromgroups=#!topic/boost-list/jQ7OjAmos_Y) While doing so I realized that leveraging C++11 lambda functions, Boost.Contract could be re-implemented without its crazy macros that alter C++ function declaration syntax. Boost.Contract still remains the only C++ library that implements *all* features of Contract Programming (a.k.a., Design by Contract or DbC): subcontracting, class invariants (also static and volatile), postconditions (with old and return values), preconditions, customizable actions on assertion failure (terminate, throw, etc.), optional assertion compilation, disable assertion checking while already checking other assertions (to avoid infinite recursion), etc. Furthermore, in its new incarnation Boost.Contract no longer uses crazy macros so it is easier to use, faster to compile, and gives readable compiler errors. For example: #include <boost/contract.hpp> int inc(int& x) { int result; boost::contract::old_ptr<int> old_x = BOOST_CONTRACT_OLDOF(x); boost::contract::guard c = boost::contract::function() .precondition([&] { BOOST_CONTRACT_ASSERT(x < std::numeric_limits<int>::max()); }) .postcondition([&] { BOOST_CONTRACT_ASSERT(x == *old_x + 1); BOOST_CONTRACT_ASSERT(result == *old_x); }) ; return result = x++; // Function body. } Or with subcontracting: #include <boost/contract.hpp> #include <vector> template<typename T> class pushable; // Arbitrary base to demo subcontracting. template<typename T> class vector #define BASES public pushable<T> : BASES { public: typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types; // Subcontracting. #undef BASES void invariant() const { // Checked in AND with base class invariants. BOOST_CONTRACT_ASSERT(size() <= capacity()); // Line 25. } virtual void push_back(T const& value, boost::contract::virtual_* v = 0) /* override */ { boost::contract::old_ptr<unsigned> old_size = BOOST_CONTRACT_OLDOF(v, size()); // Old values. boost::contract::guard c = boost::contract::public_function< override_push_back>(v, &vector::push_back, this, value) .precondition([&] { // Checked in OR with base preconditions. BOOST_CONTRACT_ASSERT(size() < max_size()); // Line 35. }) .postcondition([&] { // Checked in AND with base postconditions. BOOST_CONTRACT_ASSERT(size() == *old_size + 1); // Line 38. }) ; vect_.push_back(value); // Function body. } BOOST_CONTRACT_OVERRIDE(push_back) // For `override_push_back`. // Could program contracts for those as well. unsigned size() const { return vect_.size(); } unsigned max_size() const { return vect_.max_size(); } unsigned capacity() const { return vect_.capacity(); } private: std::vector<T> vect_; }; Full documentation and examples at: https://lcaminiti.github.io/boost-contract What do you think? Thanks, --Lorenzo P.S. The library can also be used without C++11 lambda functions (or any C++11 specific feature) but programmers have to write a fare amount of extra code to program the precondition and postcondition functors (using non-local functions, Boost.LocalFunction, Boost.Funsion, Boost.Lambda, or some other approach) so that might not useful in practice.

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[graph] Compilation error with adjacency_list and C++11
by Sebastien Loriot (GeometryFactory) 18 Jul '16

18 Jul '16

Hello, the program below does not compile at least with g++ 5.3.1 and clang++ 3.5.2-1 when using c++11 standard. If I comment line #1 it compiles. If I change #2 to undirectedS it compiles. Is there anything wrong in my code or is it a problem in boost's? Thanks, Sebastien. #include <boost/graph/adjacency_list.hpp> struct A { A(){} A(const A& ){} // #1 A& operator=(const A&){return *this;} }; typedef boost::adjacency_list<boost::listS, boost::vecS, boost::directedS, //#2 A > Graph; int main() { Graph g; boost::add_vertex(g); return 0; }

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smartptr maintained
by Karolin Varner 15 Jul '16

15 Jul '16

Hi, is smartptr still being maintained? There are four pull requests, one more than a year old. Best, Karolin Varner

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What kind of algorithms/data structures can enter in Boost
by Зайцев Александр 03 Jul '16

03 Jul '16

Hello. I am interested in developing data structures and some algorithms in Boost library. But one of the requierement for library is: "The library should be generally useful". What does it mean? I think, that i can add to the library some more data structures: suffix tree/array/automata, palindromic tree, modifications of stack/queue for getting min/max with O(1), Aho–Corasick(maybe it's algo already exist in Boost Library), maybe something else (kd-tree, for example). And algortihms: Manacker's algo for calculating palindromes number, Longest increasing subsequence, palindromic check. There are many algorithms, which i can implement to the Boost library. Also Boost.Math versus GNU MP library is very simple. In GNU MP there are many useful features. And i don't know? we need to provide these features to the Boost.Math or not. Ok, Who can explain me, what algorithms of those that i mentioned, is generally useful? What is useful for Boost, and what is useless? Thanks. -- Best regards, Zaitsev Alexander

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defect macro for thread_local?
by Oliver Kowalke 02 Jul '16

02 Jul '16

Hi, does boost provide a defect macro for thread_local (like BOOST_NO_CXX11_THREAD_LOCAL)? I couldn't find something similar int the boost macro reference. The macro would be helpful together with the feature-check to exclude compilers, that do not support the keyword thread_local (as gcc-4.7. and apple's compiler), from unit-tests. Oliver

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[1.61.0] building with Clang and c++11
by Richard Hadsell 02 Jul '16

02 Jul '16

I have downloaded 1.61.0 and want to build it with Clang. This is in my user-config: using clang : 3.5.0 : /netDISKS/master/netmt/LINUX_C65/app/clang/3.5.0/bin/clang++ : <compileflags>"-fPIC -gcc-toolchain /netDISKS/master/netmt/LINUX_C65/app/gcc/4.8.3 -Wno-overloaded-virtual -Wno-unused-function -Wno-unused-variable -Wno-c99-extensions -Wno-variadic-macros" <linkflags>"-fPIC -gcc-toolchain /netDISKS/master/netmt/LINUX_C65/app/gcc/4.8.3" ; When I build, I see warnings like these: ./boost/mpl/print.hpp:50:19: warning: in-class initialization of non-static data member is a C++11 extension [-Wc++11-extensions] const int m_x = 1 / (sizeof(T) - sizeof(T)); ^ ./boost/timer/timer.hpp:44:43: warning: 'long long' is a C++11 extension [-Wc++11-long-long] void clear() { wall = user = system = 0LL; } ^ ./boost/regex/v4/instances.hpp:124:34: warning: unknown warning group '-Wkeyword-macro', ignored [-Wunknown-pragmas] #pragma clang diagnostic ignored "-Wkeyword-macro" ^ When I add '-std=c++11' to the <compileflags> and <linkflags>, I get errors and warnings like these: clang-linux.compile.c.without-pth bin.v2/libs/container/build/clang-linux-3.5.0/release/instruction-set-core2/link-static/threading-multi/alloc_lib.o error: invalid argument '-std=c++11' not allowed with 'C/ObjC' "/netDISKS/master/netmt/LINUX_C65/app/clang/3.5.0/bin/clang++" -c -x c -O3 -Wno-inline -Wall -std=c++11 -fPIC -gcc-toolchain /netDISKS/master/netmt/LINUX_C65/app/gcc/4.8.3 -Wno-overloaded-virtual -Wno-unused-function -Wno-unused-variable -Wno-c99-extensions -Wno-variadic-macros -march=core2 -pthread -m64 -DBOOST_ALL_NO_LIB=1 -DBOOST_CONTAINER_STATIC_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/container/build/clang-linux-3.5.0/release/instruction-set-core2/link-static/threading-multi/alloc_lib.o" "libs/container/src/alloc_lib.c" libs/locale/src/shared/localization_backend.cpp:54:22: warning: 'auto_ptr' is deprecated [-Wdeprecated-declarations] std::auto_ptr<localization_backend> res(new actual_backend(backends,default_backends_)); ^ ./boost/regex/v4/instances.hpp:124:34: warning: unknown warning group '-Wkeyword-macro', ignored [-Wunknown-pragmas] #pragma clang diagnostic ignored "-Wkeyword-macro" ^ What options do I need to add or remove to build and use boost with no errors and as few warnings as possible? -- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studios http://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560

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New library? CallableTraits
by Barrett Adair 01 Jul '16

01 Jul '16

I posted about this a month ago, but I did not receive much response. Since then, I added an extended example use case, and I added a documentation section [1] that compares CallableTraits and Boost.FunctionTypes. I received some positive feedback this week in Aspen, and r/cpp also seemed to respond well [2], so I thought I'd give this another shot. Here are my questions for you: 1. Is there any interest in reviewing a future version of this for inclusion in Boost? 2. If so, does this belong in its own library, or should it be incorporated into Boost.TypeTraits or something similar? 3. What you like to see added, removed, renamed, or redesigned? I'd say CallableTraits is about 85% finished. Here's what's left: * Add INVOKE semantics to a couple of things for consistency (arity, etc) * Remove unused/undocumented code * Account for transaction_safe and C++17 noexcept * Finish/test the calling convention features * Finish/update the reference documentation * Write even more tests Cheers, Barrett [1] http://badair.github.io/callable_traits/doc/html/index.html#callable_traits… [2] https://www.reddit.com/r/cpp/comments/4ffmfs/callabletraits_never_write_ano… GitHub: https://github.com/badair/callable_traits Documentation from the top: http://badair.github.io/callable_traits/doc/html/index.html (reference section under construction)

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[build] Running 1 per N tests
by Adam Wulkiewicz 30 Jun '16

30 Jun '16

Hi, At Boost.Geometry we're using CircleCI for testing. They allow to run the tests concurently on N virtual machines. I'd like to alter my script to automatically redistribute the tests evenly across all of the machines, i.e. to run 1/N of the tests on each machine. The problem is that at Boost.Geometry we have a lot of nested project directories, i.e. b2 executed for some upper directory runs the tests in the test-suite in this directory and then follows nested projects defined by build-project directives, so runs the tests recursively. So e.g. if b2 was executed on some virtual machine for the most-top-level directory all of the tests would be built anyway. Do you have an idea how this could be solved without altering the tests structure? Is it currently somehow possible (though AFAIK it isn't) or would be possible to implement options allowing to e.g.: - run b2 only for a certain directory/Jamfile, e.g. --non-recursive - ignore arbitrary Jamfile directive, e.g. --ignore-build-project - run only 1 per N tests, an option used together with -jX but running tests only for one thread, e.g. b2 -i2 -j4 running only 1 per 4 commands starting from 2nd command ? The last option would be the most convenient for me. The tests would be divided as evenly as possible. It wouldn't require to use some workarounds i.e. traversing test directories recursively and running b2 manually for them which could result in low-quality redistribution, e.g. if some directory contained many tests and other small number of tests. Regards, Adam

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boost regression run.py fails with, fatal: Not a git repository
by Blower, Melanie 29 Jun '16

29 Jun '16

I'm trying to run.py on develop to report results with the Intel compiler. The script I use first downloads run.py. The git is failing partway through with this message Cloning into 'tools/quickbook'... Submodule path 'tools/quickbook': checked out 'c7cb99ac029593024f3f31a1ab2503820f1300d5' # Cleaning up "/localext3/mblower/sandbox/_try_dev/boost_root/bin" directory ... # Cleaning up "/localext3/mblower/sandbox/_try_dev/boost_root/bin.v2" directory ... # Cleaning up "/localext3/mblower/sandbox/_try_dev/results" directory ... # Getting sources (2016-06-29T12:24:07Z)... # Executing GIT command: /localext3/mblower/sandbox/_try_dev/boost_root> git submodule foreach "cd $toplevel && git submodule deinit $path" Entering 'libs/accumulators' fatal: Not a git repository (or any parent up to mount point /localext3) Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set). Stopping at 'libs/accumulators'; script returned non-zero status. # git_source_checkout failed with message "GIT command "git submodule foreach "cd $toplevel && git submodule deinit $path"" failed with code 256" I'm using a new server, the "master" results completed successfully last night. There's plenty of disk space. Any ideas?

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