[英]Is clang's c++11 support reliable?
尝试混合clang(Apple LLVM 6.0版(clang-600.0.56)(基于LLVM 3.5svn,目标:x86_64-apple-darwin14.0.0),c ++ 11和CGAL(通过MacPorts)时,我遇到了一个有趣的问题)。
看来我是否调用std::vector<>::reserve
将决定我的程序是否会编译。
我已经将问题简化为一个最小的例子(尽可能少的CGAL示例):
#include <vector>
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/AABB_tree.h>
#include <CGAL/AABB_traits.h>
#include <CGAL/AABB_triangle_primitive.h>
// CGAL::Epeck works fine, suggesting the problem is in CGAL::Epick
typedef CGAL::Epick Kernel;
typedef CGAL::Triangle_3<Kernel> Triangle_3;
typedef typename std::vector<Triangle_3>::iterator Iterator;
typedef CGAL::AABB_triangle_primitive<Kernel, Iterator> Primitive;
typedef CGAL::AABB_traits<Kernel, Primitive> AABB_triangle_traits;
typedef CGAL::AABB_tree<AABB_triangle_traits> Tree;
typedef typename Tree::Point_and_primitive_id Point_and_primitive_id;
typedef CGAL::Point_3<Kernel> Point_3;
template <typename BKernel>
void A()
{
const CGAL::AABB_tree<
CGAL::AABB_traits<BKernel,
CGAL::AABB_triangle_primitive<BKernel,
typename std::vector<CGAL::Triangle_3<BKernel> >::iterator
>
>
> tree;
Point_and_primitive_id pp = tree.closest_point_and_primitive(Point_3());
}
void B()
{
std::vector<Triangle_3> T;
#ifdef MAGIC
T.reserve(0);
#endif
return A<Kernel>();
}
发行:
clang++ -std=c++11 -c example.cpp -I/opt/local/include
这无法编译。 给出如下错误:
In file included from example.cpp:1:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/vector:265:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__bit_reference:15:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/algorithm:626:
In file included from /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/utility:157:
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__tuple:228:60: error:
no member named 'value' in 'std::__1::is_convertible<const CGAL::Point_3<CGAL::Epick> &,
CGAL::Point_3<CGAL::Epick> >'
is_convertible<_Tp0, _Up0>::value &&
~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/__tuple:242:14: note:
in instantiation of template class 'std::__1::__tuple_convertible_imp<true, std::__1::__tuple_types<const
CGAL::Point_3<CGAL::Epick> &, const CGAL::Vector_3<CGAL::Epick> &>,
std::__1::__tuple_types<CGAL::Point_3<CGAL::Epick>, CGAL::Vector_3<CGAL::Epick> > >' requested here
: public __tuple_convertible_imp<tuple_size<typename remove_reference<_Tp>::type>::value ==
但是,如果我对std::vector::reserve
进行这个魔术调用,则会编译 :
clang++ -std=c++11 -c example.cpp -I/opt/local/include -DMAGIC
或者通过禁用c ++ 11
clang++ -c example.cpp -I/opt/local/include
由于Apple的GCC已经过时(2007年最新的GPL v2版本,GCC 4.2.1)而不是C ++ 11功能完整(因此随附了libstdc ++),您可以通过MacPorts安装更现代版本的GCC( sudo port install gcc48
或sudo port install gcc49
),这将为您提供更现代的libstdc ++版本。 我测试了你的代码:
/opt/local/bin/g++-mp-4.8 -std=c++11 -c example.cpp -I/opt/local/include
它成功编译。
如果您更喜欢这个解决方案并希望编写更清晰的编译器 您可以使用命令gcc_select
将MacPorts的GCC设置为默认值(在我的情况下为gcc48):
sudo port select --set gcc mp-gcc48
只有一次。 然后,你可以用它来编译它
g++ -std=c++11 -c example.cpp -I/opt/local/include
在一个新的终端会议中。
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