Hello List! I have taken it into my head to use c++11 features with Qt. I am trying to use the mingw-w64 port of g++, enabling the supported c++11 features with "-std=gnu++11".
Let me note up front that even if it is not necessary to build the Qt libraries with "-std=gnu++11" (For safety and consistency, I prefer to do so, but some have suggested that it is not necessary.), I will need to be able to process Qt headers with "-std=gnu++11" set in order to compile my own code. I have been hitting some issues that have been reported in part in the past, but I haven't found any clear resolution. Any help or suggestions would be very welcome. First, I am using the recently downloaded Qt 4.8.4 source bundle: qt-everywhere-opensource-src-4.8.4.zip and a recently downloaded std::thread-enabled Ruben build of 4.8.1 g++: x86_64-w64-mingw32-gcc-4.8-stdthread-win64_rubenvb.7z The (almost) first issue I see is an ambiguous definition of swap when compiling ..\3rdparty\javascriptcore\JavaScriptCore\API\JSBase.cpp: ..\3rdparty\javascriptcore\JavaScriptCore/wtf/HashTable.h:264:83: error: 'template<class T, class U> void QTWTF::swap(std::pair<_T1, _T2>&, std::pair<_T1, _T2>&)' conflicts with previous using declaration 'template<class _T1, class _T2> void std::swap(std::pair<_T1, _T2>&, std::pair<_T1, _T2>&)' template<typename T, typename U> inline void swap(pair<T, U>& a, pair<T, U>& b) I see this issue reported (with Qt 4.8.2 and mingw 4.7.1) here: http://www.qtcentre.org/threads/50150 Note, this thread talks about a couple of issues, and the swap issue is discussed at the end. I don't see any resolution in this thread. Also, note, it doesn't appear that "-std=c++11", or similar, is being passed to the g++ command. I also see a seemingly related bug listed here: https://bugreports.qt-project.org/browse/QTBUG-26228 It carries the description: "When using clang with -stdlib=libc++ option, QtScript fails to build." and is listed as Resolved / Closed. It looks like there is a clang-directed patch (presumably for Qt 5, but I can't tell) listed here: https://qt.gitorious.org/qt/qtscript/commit/48baeef0766ba145d26d374561e152b40245f3b8 I haven't tried tweaking this patch for my specific situation, but it looks like it could work. The next issue I see (also when compiling JSBase.cpp) is an undeclared signbit: ..\3rdparty\javascriptcore\JavaScriptCore\runtime/JSImmediate.h: In static member function 'static QTJSC::JSValue QTJSC::JSImmediate::from(double)': ..\3rdparty\javascriptcore\JavaScriptCore\runtime/JSImmediate.h:493:49: error: 'signbit' was not declared in this scope if (intVal != d || (!intVal && signbit(d))) There are more issues, but that's enough for a start. (The build errored out on JSBase.cpp, so I haven't gone beyond that file.) (I should mention I already encountered and fixed the tr1 namespace issue, namely that of having std::tr1::has_trivial_constructor defined, also mentioned in the thread http://www.qtcentre.org/threads/50150. Oddly, it looks to me like this issue is caused by having "-std=gnu++11" set, even though the original poster of the http://www.qtcentre.org/threads/50150 thread did not seem to be using "-std=gnu++11" or similar.) I'm hoping that some or all of these issues have already been analyzed and addressed, even if not specifically in the context of mingw-w64. Also, could there be some common "theme" behind some or all of these issues so that they might be addressed somehow with a "global" patch? Any advice on how to move forward would be greatly appreciated. Thanks. K. Frank _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
