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

does boost support multimedia framework
by qw 22 Jul '16

22 Jul '16

Hi, Does boost support multimedia framework, just like gstreamer? Thanks! Regards Andrew

2 1

[contract] Class invariants (also for static and volatile/const-volatile public functions)
by Lorenzo Caminiti 21 Jul '16

21 Jul '16

Hello all, I would like to discuss class invariants, but also for static and volatile/const-volatile public member functions, and specifically with respect to how Boost.Contract handles them. Class invariants are important... almost as important as preconditions. For example for a vector container, class invariants specify among other things the equivalence relationship `(size() == 0) == empty()` that could be found useful by static analyzers and optimizes (also discussed in N4160): template<typename T> class vector { [[invariant: (size() == 0) == empty()]] [[invariant: size() <= capacity()]] public: void push_back(T const& value) ... { ... } }; The above contract cannot be programmed using preconditions and postconditions unless: it is repeated (together with all other invariant assertions) in pre- and postconditions of each public member functions, it is asserted with try-catches also when those functions throw, it is repeated in constructor postconditions, in destructor preconditions, and with try-catches also when destructors throw... Even if invariants are programmed in some `bool invariant() const` function to avoid repeating all invariant assertions in each pre- and postcondition, the code will be cluttered by boiler-plate code (try-catch to assert invariants on throw, etc.) and an invariant failure will just report that the invariant() function returned false, but it will not report which specific invariant condition actually failed (plus static analyzers and optimizes will not be able to parse the conditions from the invariant function): template<typename T> class vector { bool invariant() const { // But cannot distinguish which of the two assertions failed... // and cannot be used by static analyzers and optimizers. return (size() == 0) == empty() && size() <= capacity(); } public: void push_back(T const& value) ... [[requires: invariant()]] [[ensures: invariant()]] { try { ... } catch(...) { [[assert: invariant()]]; throw } } }; Class invariants cannot be effectively emulated using pre- and postconditions... they should be added to a contract framework as their own feature. In Boost.Contract: template<typename T> class vector { void invariant() const { BOOST_CONTRACT_ASSERT((size() == 0) == empty()); BOOST_CONTRACT_ASSERT(size() <= capacity()); } public: void push_back(T const& value) { boost::contract::guard c = boost::contract::public_function(*this) ... ; ... } }; Note that the above invariant function `void invariant() const` cannot be declared static or const-volatile because it will need to call queries like size(), empty(), capacity(), etc. that are const and not static or const-volatile. Thus the above invariant function, being const, cannot be called at entry and exit of static and volatile/const-volatile public functions. A contract framework for C++ should support also static and const-volatile class invariants to properly handle static and volatile/const-volatile public functions (even if static and const-volatile class invariants are not mentioned in any C++ contract proposal): * Static public functions check static class invariants at entry, at exit, and if body throws. * Volatile and const-volatile public functions check static and const-volatile class invariants (in that order) at entry, at exit, and if body throws. * Non cv-qualified and const public functions check static, const-volatile, and const class invariants (in that order) at entry, at exit, and if body throws. * Constructors check static class invariants at entry, at exit, and if body throws (because those do not require the object to be constructed). Then constructors check const-volatile and const class invariants (in that order) at exit (if body does not throw, because those require the object to be constructed). * Destructors check static class invariants at entry, at exit, and if body throws (because those do not require a constructed object). Then destructors check const-volatile and const class invariants (in that order) at entry and if body throws (because those require a constructed object). In Boost.Contract: struct a { static void static_invariant() { BOOST_CONTRACT_ASSERT(...); } void invariant() const volatile { BOOST_CONTRACT_ASSERT(...); } void invariant() const { BOOST_CONTRACT_ASSERT(...); } // Following check all static_invariant(), invariant() const volatile, and invariant() const (in that order). a() { boost::contract::guard c= boost::contract::constructor(this); } virtual ~a() { boost::contract::guard c = boost::contract::destructor(this); } void m() /* no cv qualifiers */ { boost::contract::guard c = boost::contract::public_function(*this); } void c() const { boost::contract::guard c = boost::contract::public_function(*this); } // Following check both static_invariant() and invariant() const volatile (in that order). void v() volatile { boost::contract::guard c = boost::contract::public_function(*this); } void cv() const volatile { boost::contract::guard c = boost::contract::public_function(*this); } // Following check only static_invariant(). static void s() { boost::contract::guard c = boost::contract::public_function<a>(); } }; Maybe volatile member functions are rarely used in C++ so const-volatile class invariants will also be used rarely if at all... Nevertheless, if const-volatile class invariants are not supported, it will not be possible to specify invariants for classes with volatile public functions so const-volatile class invariants should be supported for completeness. Static class invariant could instead be useful when programming contracts for the static part of the object state. In particular, Boost.Contract also supports postconditions for destructors (those should be checked by a static function because they should not access the object `this` that has been destroyed after the execution of the destructor body). Destructor postconditions are not mentioned in any contract proposal... but together with constructor and other function pre- and postconditions, and together with static class invariants, they can specify contracts for the static part of the object state. For example, consider the contracts for a class that counts the number of its object instances: struct a : private noncopyable, private nonmovable { static void static_invariant() { BOOST_CONTRACT_ASSERT((instances() != 0) == exists()); } a() { boost::contract::old_ptr<unsigned> old_instances = BOOST_CONTRACT_OLDOF(instances()); boost::contract::guard c = boost::contract::constructor(this) .postcondition([&] { BOOST_CONTRACT_ASSERT(instances() == old_instances + 1); }) ; ++instances_; } virtual ~a() { boost::contract::old_ptr<unsigned> old_instances = BOOST_CONTRACT_OLDOF(instances()); boost::contract::guard c = boost::contract::destructor(this) .postcondition([&] { // Must never use object `this`. BOOST_CONTRACT_ASSERT(instances() == old_instances - 1); }) ; --instances_; } static unsigned instances() { boost::contract::guard c = boost::contract::public_function<a>(); return instances_; } static bool exists() { boost::contract::guard c = boost::contract::public_function<a>(); return instances_ != 0; } private: static unsigned instances_; }; unsigned a::instances_ = 0; --Lorenzo

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double_ended - request formal review
by Benedek Thaler 21 Jul '16

21 Jul '16

Dear Boost, I'd like to request the review of the double_ended library. Code: https://github.com/erenon/double_ended Documentation: http://erenon.hu/double_ended The library contains two classes. Excerpt from the documentation: * `devector` is a hybrid of the standard vector and deque containers, as well as the small_vector of Boost.Container. It offers cheap (amortized constant time) insertion at both the front and back ends, while also providing the regular features of std::vector, in particular the contiguous underlying memory. In contrast to the standard vector, however, devector offers greater control over its internals. Like small_vector, it can store elements internally without dynamically allocating memory. * `batch_deque` is very similar to the standard deque, with a slight twist. It lets you specify its segment size: The size of the contiguous memory segments it uses to store its elements. This provides a consistent layout across platforms, and lets you iterate over the segments with batch operations. I'm also looking for a review manager. Thanks, Benedek

2 1

[contract] Friend functions
by Lorenzo Caminiti 19 Jul '16

19 Jul '16

Hello all, I would like to discuss contracts for friend functions and specifically how they are handled in Boost.Contract. Consider the following example: class a; class b; class data { ... friend bool deep_equal(a*, b*); bool equal(data const&); }; class a { ... friend bool deep_equal(a*, b*); data data_; }; class b { ... friend bool deep_equal(a*, b*); data data_; }; bool deep_equal(a* x, b* y) { return x->data_.equal(y->data_); } Via friendship, deep_equal can be considered to extend a and b public interfaces, but not data's public interface (in fact, deep_equal does not take instance of data as an argument). Therefore, it is reasonable to think that deep_equal should check a and b class invariants (if so... in which order?), but not data's class invariants. As discussed in N4160, that would probably require some new language feature to specify which subset of friend functions also extend a class public interface. Plus such a feature should identify some preferred order in which class invariants should be checked for a friend function that extends public interfaces of multiple classes. That seems rather complicated so I think a language proposal (like N1962) is better off going with the general rule that friends functions do not check class invariants (even if that might not always be ideal in all cases): bool deep_equal(a* x, b* y) [[requires: x && y]] // Does not check a and b (and c) invariants... even if arguably it should. { return x->data_.equal(y->data_); } In Boost.Contract: bool deep_equal(a* x, b* y) { boost::contract::guard c = boost::contract::function() .precondition([&] { BOOST_CONTRACT_ASSERT(x && y); }) ; // Does not check a and b (and c) invariants... even if arguably it should. return x->data_.equal(y->data_); } Maybe programmers could manually check a and b invariants (but then also from the function body when it throws) when those checks are truly essential for friend function: bool deep_equal(a* x, b* x) [[requires: x && y]] // Check a and b invariants in that order (if contract writes decide to), does not check c invariants. [[requires: x->invariant() && y->invariant()] [[ensures: x->invariant() && y->invariant()] { try { return x->data_.equal(y->data_); } catch(...) { [[assert: x->invariant() && y->invariant()]]; throw; } } (That seems somewhat verbose... plus it assumes that class invariants are somehow specified in a `bool invariant() const function (that can be private), or using a set of [[invariant: ...]] attributes that automatically generate such a callable `bool invariant() const` function.) This is possible in Boost.Contract: bool deep_equal(a* x, b* y) { boost::contract::guard c = boost::contract::function() .precondition([&] { BOOST_CONTRACT_ASSERT(x && y); }) ; // Check a and b invariants in that order (if contract writers decide to), does not check c invariants. boost::contract::guard inv_x = boost::contract::public_function(*x); boost::contract::guard inv_y = boost::contract::public_function(*y); return x->data_.equal(y->data_); } Finally, note that in this case preconditions are checked before entry invariants (while usually public functions check preconditions after entry invariants). That is desirable/needed for friend functions because the class object is not *this (which is always well defined and therefore subject to no precondition). For friend functions, the class object can be any computation of the friend function arguments and those arguments must be validated by preconditions before they can be used to access the class object. In the examples above, the arguments are checked to be not null by preconditions so they can be safely dereferenced to get the objects *x and *y (and in general the computations required might be even much more complex than dereferencing pointers). Thank you. --Lorenzo

1 0

[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.

6 14

[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; }

2 2

[type_index] Interest in dynamic_cast emulation?
by Chris Glover 17 Jul '16

17 Jul '16

Hi, I reached for Boost.TypeIndex the other day expecting to find a kind of dynamic_cast I could use in the absence of Rtti. I didn't find it, so I wrote something to emulate it using type_index internally. It's working, but before I go too far and clean this up and possibly submit a pull request, I would like to gauge if there's interest in such a thing or if there's some fundamental reason why it doesn't exist. So, thoughts? Thanks, -- chris

5 8

[contract] Strong exception safety guarantees
by Lorenzo Caminiti 15 Jul '16

15 Jul '16

Hello all, I've been considering adding a .except(...) construct to Boost.Contract that will allow to specify conditions to check at function exit but when the function body throws (in contrast to postconditions that are checked at function exit but only when the function body does not throw). I think .except(...) could be used to assert strong exception safety guarantees... (note that class invariants are already checked at exit of public functions and also when the public function bodies throw, but invariants are suited to assert only basic, and not strong, exception safety guarantees). That might help addressing a point made in P0147R0 under the "Contracts and Exceptions" section: ``Some operations make stronger exception safety claims. In particular, they claim that an exception thrown from a member function will leave the state of an object unchanged from its state on function entry. If we invalidate postconditions on exceptions, we appear to have no mechanism to describe strong exception safety.'' For example, the following swap ensures to leave its arguments unchanged when it throws: void swap(std::string& a, std::string& b) { boost::contract::old_ptr<std::string> old_a = BOOST_CONTRACT_OLDOF(a); boost::contract::old_ptr<std::string> old_b = BOOST_CONTRACT_OLDOF(b); boost::contract::guard c = boost::contract::function() .postcondition([&] { // Checked at function exit but only if body does not throw. BOOST_CONTRACT_ASSERT(a == *old_b); BOOST_CONTRACT_ASSERT(b == *old_a); }) .except([&] { // Checked if body throws (strong exception safety guarantees). BOOST_CONTRACT_ASSERT(a == *old_a); BOOST_CONTRACT_ASSERT(b == *old_b); }) ; ... // Body implementation (which might throw). } Would this be beneficial? Thanks, --Lorenzo

2 5

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

2 3

[graph] A* implementation doesn't follow the algorithm
by Nick Lamprianidis 14 Jul '16

14 Jul '16

For the A* algorithm holds that when a new vertex v is reached through a shorter path, then v is added to the open set. But looking at the boost graph's A* implementation, which is based on the BFS algorithm, one can see that a target vertex is added to the priority queue, regardless of whether the relevant edge is being relaxed. This creates the following situation: The execution starts and you get to a point where you know you cannot reach the goal: no vertices with finite cost in the priority queue. Normally, you would expect that the priority queue is empty and thus the execution ends. Instead, the execution continues, since the priority queue is filled with all those vertices (with infinite cost) that got added for no reason. In an application where the state of a target vertex v gets set when an associated edge is being relaxed, a problem arises. In the situation mentioned above, uninitialized vertices reach the visitor's examine_vertex method. Unless you know what's really happening, so you can take care to add a test condition to exit, it leaves you wondering what's going wrong. I propose that you either change the implementation or at least update the documentation (pseudocode). -- Nick Lamprianidis http://paign10.me

3 2

[log][regression] Error with Boost.Lob build jamfile breaks MinGW regression tester in develop
by Ion Gaztañaga 13 Jul '16

13 Jul '16

Hi, My develop branch regression runner fails whereas the master one works fine. The develop runner fails with all Mingw targets (msvc 7.1 works fine), with this error: ************************************ # Starting tests ("c:\boost\develop\boost_bb\src\engine\bin.ntx86\bjam.exe" "-sBOOST_BUILD_PATH=c:\boost\develop;c:\boost\develop\boost_bb\src" "-sBOOST_ROOT=c:\boost\develop\boost_root" "--boost=c:\boost\develop\boost_root" "--boost-root=c:\boost\develop\boost_root" "--boost-build=c:\boost\develop\boost_bb\src" "--debug-configuration" -l300 toolset=gcc-6.1c++14 -d2 preserve-test-targets=off --dump-tests -j3 --abbreviate-paths debug-symbols=off -m64 "--build-dir=c:\boost\develop\results" >>"c:\boost\develop\results\bjam.log" 2>&1)... c:\boost\develop\boost_root\status> "c:\boost\develop\boost_bb\src\engine\bin.ntx86\bjam.exe" "-sBOOST_BUILD_PATH=c:\boost\develop;c:\boost\develop\boost_bb\src" "-sBOOST_ROOT=c:\boost\develop\boost_root" "--boost=c:\boost\develop\boost_root" "--boost-root=c:\boost\develop\boost_root" "--boost-build=c:\boost\develop\boost_bb\src" "--debug-configuration" -l300 toolset=gcc-6.1c++14 -d2 preserve-test-targets=off --dump-tests -j3 --abbreviate-paths debug-symbols=off -m64 "--build-dir=c:\boost\develop\results" 1>>"c:\boost\develop\results\bjam.log" 2>&1 # Running Boost.Build tests Traceback (most recent call last): File "run.py", line 71, in <module> runner(root) File "c:\boost\develop\boost_regression_src\regression.py", line 287, in __init__ self.main() File "c:\boost\develop\boost_regression_src\regression.py", line 624, in main getattr(self,action_m)() File "c:\boost\develop\boost_regression_src\regression.py", line 589, in command_regression self.command_test() File "c:\boost\develop\boost_regression_src\regression.py", line 368, in command_test self.command_test_boost_build() File "c:\boost\develop\boost_regression_src\regression.py", line 410, in command_test_boost_build "boost/bin.v2/libs/any/test/any_test.test")); WindowsError: [Error 3] The system cannot find the path specified: 'c:\\boost\\develop\\results\\boost/bin.v2/libs/any/test/any_test.test/*.*' ************************************ That path ("..libs/any/test/any_test.test/) is hardcoded in regression.py, but it's not generated in my bin.v2 so it's reasonable an error saying that the system can't find the path ;-) It seems that error occurs before boost.build tests, as bjam.log shows: ************************************ C:/boost/develop/boost_bb/src/build\targets.jam:1077: in evaluate-requirements from module targets error: Can not evaluate conditional properties <conditional>@Jamfile<C:\boost\develop\boost_root>%Jamfile<C:\boost\develop\boost_root>.handle-static-runtime <conditional>@Jamfile<C:\boost\develop\boost_root>%boostcpp.deduce-address-model <conditional>@Jamfile<C:\boost\develop\boost_root>%boostcpp.deduce-architecture <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.check-instruction-set <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.check-message-compiler <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.check-pthread-mutex-robust <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.check-visibility <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.select-arch-specific-sources <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.select-platform-specific-sources <conditional>@Jamfile<C:\boost\develop\boost_root\libs\log\build>%Jamfile<C:\boost\develop\boost_root\libs\log\build>.select-regex-backend <link>shared:<define>BOOST_LOG_DLL <target-os>cygwin:<define>BOOST_USE_WINDOWS_H <target-os>cygwin:<define>NOMINMAX <target-os>cygwin:<define>SECURITY_WIN32 <target-os>cygwin:<define>WIN32_LEAN_AND_MEAN <target-os>cygwin:<define>__USE_W32_SOCKETS <target-os>cygwin:<library>/boost/log//advapi32 <target-os>cygwin:<library>/boost/log//mswsock <target-os>cygwin:<library>/boost/log//ws2_32 <target-os>freebsd:<library>/boost/log//rt <target-os>hpux:<define>_XOPEN_SOURCE=600 <target-os>hpux:<library>/boost/log//ipv6 <target-os>linux:<define>_XOPEN_SOURCE=600 <target-os>linux:<library>/boost/log//rt <target-os>qnxnto:<library>/boost/log//socket <target-os>solaris:<define>_XOPEN_SOURCE=500 <target-os>solaris:<define>__EXTENSIONS__ <target-os>solaris:<library>/boost/log//nsl <target-os>solaris:<library>/boost/log//socket <target-os>windows:<define>BOOST_USE_WINDOWS_H <target-os>windows:<define>NOMINMAX <target-os>windows:<define>SECURITY_WIN32 <target-os>windows:<define>WIN32_LEAN_AND_MEAN <target-os>windows:<library>/boost/log//advapi32 <target-os>windows:<library>/boost/log//mswsock <target-os>windows:<library>/boost/log//ws2_32 <threading>multi:<library>/boost/atomic//boost_atomic <threading>multi:<library>/boost/thread//boost_thread <threading>single:<define>BOOST_LOG_NO_THREADS <toolset>clang:<cxxflags>-ftemplate-depth-1024 <toolset>como-linux:<define>_GNU_SOURCE=1 <toolset>como:<link>static <toolset>darwin:<cxxflags>-ftemplate-depth-1024 <toolset>gcc,<target-os>cygwin:<linkflags>-Wl,--enable-auto-import <toolset>gcc,<target-os>windows:<linkflags>-Wl,--enable-auto-import <toolset>gcc:<cxxflags>-fno-strict-aliasing <toolset>gcc:<cxxflags>-ftemplate-depth-1024 <toolset>intel-darwin:<cxxflags>-wd177,780,2196,1782,193,304,981,1418,411,734,279 <toolset>intel-linux:<cxxflags>-wd177,780,2196,1782,193,304,981,1418,411,734,279 <toolset>intel-win:<cxxflags>/Qwd177,780,2196,1782,193,304,981,1418,411,734,279 <toolset>intel-win:<define>_CRT_SECURE_NO_DEPRECATE <toolset>intel-win:<define>_CRT_SECURE_NO_WARNINGS <toolset>intel-win:<define>_SCL_SECURE_NO_DEPRECATE <toolset>intel-win:<define>_SCL_SECURE_NO_WARNINGS <toolset>msvc,<runtime-link>shared:<threading>multi <toolset>msvc:<cxxflags>/bigobj <toolset>msvc:<cxxflags>/wd4003 <toolset>msvc:<cxxflags>/wd4456 <toolset>msvc:<cxxflags>/wd4459 <toolset>msvc:<cxxflags>/wd4503 <toolset>msvc:<define>_CRT_SECURE_NO_DEPRECATE <toolset>msvc:<define>_CRT_SECURE_NO_WARNINGS <toolset>msvc:<define>_SCL_SECURE_NO_DEPRECATE <toolset>msvc:<define>_SCL_SECURE_NO_WARNINGS <toolset>pgi:<library>/boost/log//rt C:/boost/develop/boost_bb/src/build\targets.jam:1112: in common-properties2 from module targets C:/boost/develop/boost_bb/src/build\targets.jam:977: in targets.common-properties from module targets C:/boost/develop/boost_bb/src/build\targets.jam:1303: in class(a)basic-target.generate from module object(typed-target)@1504 C:/boost/develop/boost_bb/src/build\targets.jam:774: in generate-really from module object(main-target)@49045 C:/boost/develop/boost_bb/src/build\targets.jam:746: in class(a)main-target.generate from module object(main-target)@49045 C:/boost/develop/boost_bb/src/build\targets.jam:895: in targets.generate-from-reference from module targets C:/boost/develop/boost_bb/src/build\targets.jam:1266: in generate-dependencies from module object(typed-target)@14269 C:/boost/develop/boost_bb/src/build\targets.jam:1320: in class(a)basic-target.generate from module object(typed-target)@14269 C:/boost/develop/boost_bb/src/build\targets.jam:774: in generate-really from module object(main-target)@49008 C:/boost/develop/boost_bb/src/build\targets.jam:746: in class(a)main-target.generate from module object(main-target)@49008 C:/boost/develop/boost_bb/src/build\targets.jam:895: in targets.generate-from-reference from module targets C:/boost/develop/boost_bb/src/build\targets.jam:1266: in generate-dependencies from module object(alias-target-class)@36618 C:/boost/develop/boost_bb/src/build\targets.jam:1323: in class(a)basic-target.generate from module object(alias-target-class)@36618 C:/boost/develop/boost_bb/src/build\targets.jam:774: in generate-really from module object(main-target)@36634 C:/boost/develop/boost_bb/src/build\targets.jam:746: in class(a)main-target.generate from module object(main-target)@36634 C:/boost/develop/boost_bb/src/build\targets.jam:272: in class(a)project-target.generate from module object(project-target)@2141 c:/boost/develop/boost_bb/src\build-system.jam:714: in load from module build-system C:\boost\develop\boost_bb\src/kernel\modules.jam:295: in import from module modules C:\boost\develop\boost_bb\src/kernel/bootstrap.jam:139: in boost-build from module C:\boost\develop\boost_root\boost-build.jam:17: in module scope from module ************************************ I can't see why this Jamfile from Boost.Log is accepted when MSVC-7.1 is the target but fails when MinGW is the selected target. I could neither t deduce what is the failing piece of the configuration. The same error happens with a wide range of MINGW targets: GCC-3.4, GCC-4.1, GCC-4.2, GCC-4.3, GCC-4.4, GCC-4.5, GCC-4.6, GCC-4.7, GCC-4.8, GCC-4.9, GCC-5.1, GCC-5.2, GCC-5.3 and GCC-6.1. Any clue on what can be happening and how can it be fixed? Attached regression logs for a failed MINGW regression with GCC 6.1. Best, Ion

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[regression][winapi] Tests not being run
by Andrey Semashev 11 Jul '16

11 Jul '16

Hi, I wrote about it before, but now the problem becomes more weird. The problem is that the tests for Boost.WinAPI are not being run for some reason. What's weird is that now there is one test in the matrix (http://www.boost.org/development/tests/develop/developer/winapi.html) that isn't part of the Boost.WinAPI test suite. I assume that entry is part of the formal checks for the library conformance, since it is present for all libraries. Could someone please have a look why the tests for Boost.WinAPI are not being executed? PS: The link for the __boost_check_library__ entry is broken: https://github.com/boostorg/winapi/blob/developstatus/boost_check_library.py I believe, there's a slash missing between develop and status, and also the repository name should be boost rather than winapi.

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[TypeErasure] Merging pull-requests
by Deniz Bahadir 11 Jul '16

11 Jul '16

Hello everyone, Hello Steven, a view weeks ago I reported some bugs of Boost.TypeErasure [1,2] and provided pull-requests [3,4] which fix these. I just wanted to bring these to attention so that they might get merged and find their way into the next Boost release. Thanks, Deniz PS: There is another open pull-request [5] (by John Maddock) which seems to be even more urgent. [1] https://svn.boost.org/trac/boost/ticket/12291 [2] https://svn.boost.org/trac/boost/ticket/12292 [3] https://github.com/boostorg/type_erasure/pull/9 [4] https://github.com/boostorg/type_erasure/pull/10 [5] https://github.com/boostorg/type_erasure/pull/11 -- BENOCS GmbH Dipl.-Inform. Deniz Bahadir Winterfeldtstr. 21 10781 Berlin Germany Phone: +49 - 30 / 577 0004-22 Email: deniz.bahadir(a)benocs.com www.benocs.com Board of Management: Michael Wolz, Dr.-Ing. Oliver Holschke, Dr.-Ing. Ingmar Poese Commercial Register: Amtsgericht Bonn HRB 19378

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[Hana/Fit] about constexpr/noexcept on equivalent functions to std::overload
by Vicente J. Botet Escriba 08 Jul '16

08 Jul '16

Hi, On the C++ standard meating in Oulu, we decided to make the std::overload function constexpr and conditionaly noexcept and ensure that the overloaded functions shall be constexpr if the stored finctions are. I don't find in the reference documentation of Hana and Fit any reference of whether the overloaded functions preserve constexpr or not. There is a reedit post [1] and CWG issue 1581 [2] that are related. Could the authors clarify? What other think? Best, Vicente [1] https://www.reddit.com/r/cpp/comments/35g7f6/c17_progress_update/cr4mvid [2] http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#1581

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[config] msvc-14 config changes heads up
by John Maddock 08 Jul '16

08 Jul '16

I've just pushed some changes to develop so that MSVC-14.0 update 3 no longer defines: BOOST_NO_CXX14_VARIABLE_TEMPLATES BOOST_NO_SFINAE_EXPR BOOST_NO_TWO_PHASE_NAME_LOOKUP As far as I can tell, these cause no new regressions in develop, please let me know if I've missed something. I haven't stopped defining BOOST_NO_CXX11_CONSTEXPR as it causes new failures: * Multiprecision, one new failure when using constexpr features, looks harmless. * Metaparse, causes the compiler to run out of resources on a couple of tests - these test non-default values of BOOST_METAPARSE_LIMIT_STRING_SIZE and are probably harmless. * Type_erasure, causes one new runtime failure. * Chrono, nothing much compiles - this one is the showstopper and needs investigating - any takers? Best, John.

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[qvm] help with tests
by Emil Dotchevski 06 Jul '16

06 Jul '16

It appears that the QVM tests are broken somehow but it isn't clear to me what might be wrong. It shows "pass" next to __boost_check_library__, but there are no results for the actual tests. It used to work fine earlier -- this issue might be related somehow to a previous problem, where I had a build directory without realizing that the test framework recognized that name and did things I did not intend; so I renamed the build directory to bld. Can someone help me fix this? Thanks, Emil

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Re: [boost] Boost numeric conversion - unary function deprecated or removed for C++17
by Brandon Kohn 06 Jul '16

06 Jul '16

Sent from Mail for Windows 10 From: Paul A. Bristow Sent: Monday, July 4, 2016 12:48 PM To: boost(a)lists.boost.org Subject: [boost] Boost numeric conversion - unary function deprecated or removed for C++17 >Can anyone help please. I’ve pushed fixes for this. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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Boost numeric conversion - unary function deprecated or removed for C++17
by Paul A. Bristow 06 Jul '16

06 Jul '16

I need to use C++17 (or MSVC std:c++latest) for other reasons, but I am blocked on MSVC by failure to compile converter.hpp It works OK on GCC 6.1.1 but not on VS2015 update 3 http://stackoverflow.com/questions/33114656/replacement-for-binary-function http://stackoverflow.com/questions/33114656/replacement-for-binary-function I suspect that GCC has not yet removed the deprecated unary_function but that MSVC correctly has removed it? Updating this looks above my pay grade. Can anyone help please. Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

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[1.61.0][container] Error compiling alloc_lib.c with -std=c++11
by Richard Hadsell 05 Jul '16

05 Jul '16

I am trying to build Boost 1.61.0 with Clang and C++11 features. Other parts of the library warn about using C++11 features, if I do not build with the option -std=c++11. However, this C source file gives an error, and I assume it does not build at all: clang-linux.compile.c.without-pth bin.v2/libs/container/build/clang-linux-3.5.0/release/instruction-set-core2/threading-multi/alloc_lib.o error: invalid argument '-std=c++11' not allowed with 'C/ObjC' "[snip]clang++" -c -x c -O3 -Wno-inline -Wall -std=c++11 -fPIC -gcc-toolchain [snip]gcc/4.8.3 -Wno-[snip] -march=core2 -pthread -fPIC -m64 -DBOOST_ALL_NO_LIB=1 -DBOOST_CONTAINER_DYN_LINK=1 -DNDEBUG -I"." -c -o "bin.v2/libs/container/build/clang-linux-3.5.0/release/instruction-set-core2/threading-multi/alloc_lib.o" "libs/container/src/alloc_lib.c" ...failed clang-linux.compile.c.without-pth bin.v2/libs/container/build/clang-linux-3.5.0/release/instruction-set-core2/threading-multi/alloc_lib.o... These are the options from my user-config: using clang : 3.5.0 : [snip]/clang++ : <compileflags>"-std=c++11 -fPIC -gcc-toolchain [snip]/gcc/4.8.3 -Wno-[snip]" <linkflags>"-fPIC -gcc-toolchain [snip]/gcc/4.8.3" ; I don't see a way to provide C++-only flags or C-only flags. Actually, I thought that all Boost source files would be C++. -- Dick Hadsell 203-992-6320 Fax: 203-992-6001 Reply-to: hadsell(a)blueskystudios.com Blue Sky Studioshttp://www.blueskystudios.com 1 American Lane, Greenwich, CT 06831-2560

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[meta] Hidden libraries.
by Daniel James 04 Jul '16

04 Jul '16

I just noticed that 'detail' and 'winapi' have started turning up in the library lists because they've added metadata files. We've always hidden these libraries in the past, so I'm thinking of adding an extra field to mark them as private/hidden libraries. Probably just something like: { "key": "detail", "name": "Detail", "private": true /* the rest.... */ } Any opinions?

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[release] please add fiber to master
by Oliver Kowalke 03 Jul '16

03 Jul '16

Hello admins, I'd like to ask you to add boost.fiber to the master branch so that it will become part of the next boost release (1.62). thank you in advance, Oliver

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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

3 4

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

5 6

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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