September 2015 - Boost-users

program_option parsing error
by Marek Skalický 30 Sep '15

30 Sep '15

Hello everyone, I have a question about program_option library. If I have argv=["binaryname", "--port", "5"] and port have set default_value=6 and implicit_value=7 what should be the value of port after parsing argv? I am asking because this test https://github.com/mongodb/mongo/blob/0481c958daeb2969800511e7475dc66986fa9… is failing with boost 1.59 (with boost 1.58 it is passing). Does someone please know what changed in this new version? Thank you, Marek

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Is there any support for measuring or checking resource utilization in the boost utf?
by Victor Yankee 29 Sep '15

29 Sep '15

Is there any support for measuring or checking resource utilization, especially CPU usage and memory (either absolute amounts or percentages would be ok) in the boost utf?

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bug in boost or in gcc-5.2.0 ?
by renaud lepere 29 Sep '15

29 Sep '15

I have a strange problem with mingw-w64, gcc-5.2.0 in 32bits on windows in release. The following code leads to a crash (it is working in 64 bits and in debug). The adress of return in the stack seems to be broken. I was not able to reduce it more than this, and in particular I am not able to remove BOOST_CHECK_CLOSE (using BOOST_CHECK_EQUAL works). This can be either a bug in gcc (false code generation) or something else. How can I investigate ? #define BOOST_TEST_MODULE MyTest #include <boost/test/unit_test.hpp> #include <iostream> struct P { P(double x_, double y_): x(x_), y(y_) {} double x; double y; }; struct Seg { Seg(const P & o_, const P & e_): o(o_), e(e_) {} P o; P e; }; void f() { auto Check = [](const Seg & s1, const Seg & s2, bool expected_common_cut, double expected_length) { std::cerr << expected_length << std::endl; BOOST_CHECK_CLOSE(1e-3, 1e-4, .1); }; Check(Seg(P(0, 0), P(100, 0)), Seg(P(0, 0), P(100, 0)), false, 0.0); Check(Seg(P(0, 0), P(100, 0)), Seg(P(100, 0), P(0, 0)), true, 100.0); std::cerr << "STILL LEAVING !" << std::endl; } void g() { std::cerr << "BEFORE CRASH" << std::endl; f(); std::cerr << "NEVER PRINTED" << std::endl; } BOOST_AUTO_TEST_CASE( my_test ) { g(); }

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Heap: what is expected from T?
by Akim Demaille 28 Sep '15

28 Sep '15

Hi, I'm using a heap whose elements are value_type from a map; hence the key type is const. Some heaps seem to accept this gracefully, other just fail to compile. Is this expected? I saw no requirement about T in the documentation. This is Boost 1.59 from Mac Ports, on OS X. $ cat foo.cc #include <tuple> #include <string> #include <boost/heap/priority_queue.hpp> #include <boost/heap/fibonacci_heap.hpp> int main() { using datum_t = std::tuple<const std::string>; { using queue_t = boost::heap::fibonacci_heap<datum_t>; auto q = queue_t{}; q.emplace("foo"); } { using queue_t = boost::heap::priority_queue<datum_t>; auto q = queue_t{}; q.emplace("foo"); } } $ clang++-mp-3.7 -std=c++11 /tmp/foo.cc -isystem /opt/local/include In file included from /tmp/foo.cc:1: /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/tuple:283:19: error: no viable overloaded '=' value = _VSTD::forward<_Tp>(__t); ~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/tuple:485:45: note: in instantiation of function template specialization 'std::__1::__tuple_leaf<0, const std::__1::basic_string<char>, false>::operator=<const std::__1::basic_string<char> >' requested here __swallow(__tuple_leaf<_Indx, _Tp>::operator=(_VSTD::forward<_Tp>(static_cast<__tuple_leaf<_Indx, _Tp>&>(__t).get()))...); ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/tuple:498:29: note: in instantiation of member function 'std::__1::__tuple_impl<std::__1::__tuple_indices<0>, const std::__1::basic_string<char> >::operator=' requested here class _LIBCPP_TYPE_VIS_ONLY tuple ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/algorithm:4848:5: note: in instantiation of function template specialization 'std::__1::__sift_up<boost::heap::detail::heap_base<std::__1::tuple<const std::__1::basic_string<char> >, std::__1::less<std::__1::tuple<const std::__1::basic_string<char> > >, false, unsigned long, false> &, std::__1::__wrap_iter<std::__1::tuple<const std::__1::basic_string<char> > *> >' requested here __sift_up<_Comp_ref>(__first, __last, __comp, __last - __first); ^ /opt/local/include/boost/heap/priority_queue.hpp:261:14: note: in instantiation of function template specialization 'std::__1::push_heap<std::__1::__wrap_iter<std::__1::tuple<const std::__1::basic_string<char> > *>, boost::heap::detail::heap_base<std::__1::tuple<const std::__1::basic_string<char> >, std::__1::less<std::__1::tuple<const std::__1::basic_string<char> > >, false, unsigned long, false> >' requested here std::push_heap(q_.begin(), q_.end(), static_cast<super_t const &>(*this)); ^ /tmp/foo.cc:17:7: note: in instantiation of function template specialization 'boost::heap::priority_queue<std::__1::tuple<const std::__1::basic_string<char> >, boost::parameter::void_, boost::parameter::void_, boost::parameter::void_, boost::parameter::void_>::emplace<char const (&)[4]>' requested here q.emplace("foo"); ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/string:1376:19: note: candidate function not viable: 'this' argument has type 'const std::__1::basic_string<char>', but method is not marked const basic_string& operator=(const basic_string& __str); ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/string:1379:19: note: candidate function not viable: 'this' argument has type 'const std::__1::basic_string<char>', but method is not marked const basic_string& operator=(basic_string&& __str) ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/string:1383:45: note: candidate function not viable: 'this' argument has type 'const std::__1::basic_string<char>', but method is not marked const _LIBCPP_INLINE_VISIBILITY basic_string& operator=(const value_type* __s) {return assign(__s);} ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/string:1384:19: note: candidate function not viable: 'this' argument has type 'const std::__1::basic_string<char>', but method is not marked const basic_string& operator=(value_type __c); ^ /opt/local/libexec/llvm-3.7/bin/../include/c++/v1/string:1387:19: note: candidate function not viable: 'this' argument has type 'const std::__1::basic_string<char>', but method is not marked const basic_string& operator=(initializer_list<value_type> __il) {return assign(__il.begin(), __il.size());} ^ 1 error generated. Thanks in advance.

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[multi_index_container] Using equal_range with hashed indices
by Muruganand Karthikeyan 28 Sep '15

28 Sep '15

Hello! std::equal_range requires that the container be pre-sorted ( http://www.cplusplus.com/reference/algorithm/equal_range/) How does multi-index container handle this scenario with respect to hashed non-unique indices. The reason I ask is since I'm facing a situation with equal_range. Please see below code - typedef bmi< UserIdEntry, indexed_by< hashed_non_unique<tag<id1_id2>, composite_key<UserIdEntry, BMI_MEMBER(UserIdEntry, std::string, id1), BMI_MEMBER(UserIdEntry, std::string, id2) > > > > UserIdContainer; typedef UserIdContainer::index<id1_id2>::type IndexById1Id2; typedef IndexById1Id2::const_iterator IndexById1Id2_it; std::pair<IndexById1Id2_it, IndexById1Id2_it> entries = indexById1Id2.equal_range(make_tuple(id1_val, id2_val)); I'm seeing that *sometimes* entries.first equals indexById1Id2.end() and entries.second does not equal indexById1Id2.end(). The lookup is valid - meaning I've verified that there is at-least one entry which should be caught by the equal_range. I'm guessing the iterators' values are swapped. (second should be pointing to first and first should be pointing to second) What could be the reason for this? Thanks, MK.

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[multi_index_container] Using modify_key vs modify
by Muruganand Karthikeyan 28 Sep '15

28 Sep '15

Hello! Under what circumstances should we use modify_key? I believe we can achieve the same result using modify, so what is the advantage in using modify_key? Thanks, MK. -- Anand's signature

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Crash in managed_shared_memory
by Abhishek Kumar Pandey 28 Sep '15

28 Sep '15

Hi, I am using managed_shared_memory in my program. The program runs fine if only one instance is used. However if more than one instance is used then one instance dies randomly. The instance dies at the following code : char_string key_object(keyHashStr.c_str(), alloc_inst3); The sample program is : ----------------------- #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/containers/string.hpp> #include <string> #include <iostream> #define RESERVED_BUFFER_SIZE_WRITE (8 * 0x0100000) namespace bip = boost::interprocess; //Typedefs of allocators and containers typedef bip::allocator<char, bip::managed_shared_memory::segment_manager> char_allocator; typedef bip::basic_string<char, std::char_traits<char>, char_allocator> char_string; int main() { bip::managed_shared_memory m_sharedMemUsage(bip::open_or_create, "MyBookkeeper", 2 * RESERVED_BUFFER_SIZE_WRITE); char_allocator alloc_inst3(m_sharedMemUsage.get_segment_manager()); for (int count = 0; count < 100000; ++count) { char_string key_obect("AAAAAAAAAAAAAAAAAAAAAAA", alloc_inst3); } } ----------------------- Please let me know if I am missing something in this program. Regards, Abhishek

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annoying warnings with mingw-w64 gcc-5.2.0
by renaud lepere 27 Sep '15

27 Sep '15

When I compile my code with gcc version 5.2.0 (x86_64-posix-seh-rev0, Built by MinGW-W64 project), I have annoying warnings with boost/utf and boost/asio (1.59). For example if I compile this simple file : #define BOOST_TEST_MODULE ExactSuite #include "boost/test/unit_test.hpp" I get : c:\Users\Renaud\nest\external\boost_1_59_0/boost/test/unit_test_log.hpp:130:28: warning: 'boost::unit_test::{anonymous}::unit_test_log' defined but not used [-Wunused-variable] BOOST_TEST_SINGLETON_INST( unit_test_log ) I can add #pragma GCC diagnostic ignored "-Wunused-variable" just before the include but it seems strange (and I have to do it in few other files). Does someone have similar problem ? or a better fix ?

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Become a Library Maintainer
by Alex Olivas 27 Sep '15

27 Sep '15

Hey All, This was just announced this week at CppCon (originally proposed at C++Now, by Robert Ramey). There's a new program and process to allow teams, who may be maintaining boost libraries internally, to become official maintainers. These are libraries that are currently being maintained by the Boost Community Maintenance Team (https://svn.boost.org/trac/boost/wiki/CommunityMaintenance) : * Boost.ConceptCheck * Boost.DateTime * Boost.DisjointSet * Boost.DynamicBitset * Boost.Format * Boost.Function * Boost.Logic * Boost.MPL * Boost.PropertyMap * Boost.Signals (which is deprecated) * Boost.Tokenizer More information about the program can be found here: http://beta.boost.org/community/official_library_maintainer_program.html If you're interested in becoming a Boost Library Official Maintiner, please send me an email. Thanks, Alex.

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[Boost-announce] Compile and run Boost examples online
by Antony Polukhin 25 Sep '15

25 Sep '15

Hi all, I've just launched the beta version of online examples for the "Boost Application Development Cookbook": http://apolukhin.github.io/Boost-Cookbook-4880OS/ There you can do online compilation of Boost related code, run examples, freely experiment with code from the book, read intros for the code and play around with the Boost libraries. I hope the site would be useful! P.S.: If you wish to report an error or wish to have some functionality added to the site, use the "Issues" link at https://github.com/apolukhin/Boost-Cookbook-4880OS or even make a pull request. P.P.S.: Intros for Chapters 7-12 are missing at this moment. I'll add them in a few months, sorry for the delay. -- Best regards, Antony Polukhin

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