我实现了一个非常基础的ParallelFor算法，如下所示：
inline void ParallelFor( const size_t startIdx, const size_t endIdx, std::function< void( size_t ) >&& fn, const size_t numThreads = std::thread::hardware_concurrency() )
{
const size_t portion = std::max( 1, (endIdx - startIdx) / numThreads );
std::vector< std::thread > threads;
for ( size_t i = startIdx; i < endIdx; i += portion )
{
int from = i;
int to = (i + portion) <= endIdx ? (i + portion) : endIdx;
threads.push_back( std::thread( [=,&fn]()
{
for ( int j = from; j < to; ++j )
fn( j );
} ) );
}
std::for_each( threads.begin(), threads.end(), []( std::thread& x )
{
x.join();
} );
}
但是，当我构建它时，它说threads.push_back函数“试图引用已删除的函数”。
我不明白我在做什么错。有人可以指出我要去哪里了吗？
编辑：编译器是VStudio 2015
错误还有很多，如下所示：
1>C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(657): error C2280: 'std::thread::thread(const std::thread &)': attempting to reference a deleted function
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\thread(73): note: see declaration of 'std::thread::thread'
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(775): note: see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,const std::thread&>(_Objty *,const std::thread &)' being compiled
1> with
1> [
1> _Ty=std::thread,
1> _Objty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(775): note: see reference to function template instantiation 'void std::allocator<_Ty>::construct<_Objty,const std::thread&>(_Objty *,const std::thread &)' being compiled
1> with
1> [
1> _Ty=std::thread,
1> _Objty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(920): note: see reference to function template instantiation 'void std::allocator_traits<_Alloc>::construct<_Ty,const std::thread&>(std::allocator<_Ty> &,_Objty *,const std::thread &)' being compiled
1> with
1> [
1> _Alloc=std::allocator<std::thread>,
1> _Ty=std::thread,
1> _Objty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory0(920): note: see reference to function template instantiation 'void std::allocator_traits<_Alloc>::construct<_Ty,const std::thread&>(std::allocator<_Ty> &,_Objty *,const std::thread &)' being compiled
1> with
1> [
1> _Alloc=std::allocator<std::thread>,
1> _Ty=std::thread,
1> _Objty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory(379): note: see reference to function template instantiation 'void std::_Wrap_alloc<std::allocator<_Ty>>::construct<std::thread,const std::thread&>(_Ty *,const std::thread &)' being compiled
1> with
1> [
1> _Ty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory(379): note: see reference to function template instantiation 'void std::_Wrap_alloc<std::allocator<_Ty>>::construct<std::thread,const std::thread&>(_Ty *,const std::thread &)' being compiled
1> with
1> [
1> _Ty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory(416): note: see reference to function template instantiation '_FwdIt std::_Uninit_copy<_InIt,_FwdIt,std::allocator<_Ty>>(_InIt,_InIt,_FwdIt,std::_Wrap_alloc<std::allocator<_Ty>> &,std::_Nonscalar_ptr_iterator_tag)' being compiled
1> with
1> [
1> _FwdIt=std::thread *,
1> _InIt=const std::thread *,
1> _Ty=std::thread
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\xmemory(427): note: see reference to function template instantiation '_FwdIt std::_Uninit_copy<const std::thread*,_Iter,_Alloc>(_InIt,_InIt,_FwdIt,_Alloc &)' being compiled
1> with
1> [
1> _FwdIt=std::thread *,
1> _Iter=std::thread *,
1> _Alloc=std::_Wrap_alloc<std::allocator<std::thread>>,
1> _InIt=const std::thread *
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\vector(1672): note: see reference to function template instantiation '_FwdIt std::_Uninitialized_copy<_Iter,std::thread*,std::_Wrap_alloc<std::allocator<_Ty>>>(_InIt,_InIt,_FwdIt,_Alloc &)' being compiled
1> with
1> [
1> _FwdIt=std::thread *,
1> _Iter=std::_Vector_const_iterator<std::_Vector_val<std::_Simple_types<std::thread>>>,
1> _Ty=std::thread,
1> _InIt=std::_Vector_const_iterator<std::_Vector_val<std::_Simple_types<std::thread>>>,
1> _Alloc=std::_Wrap_alloc<std::allocator<std::thread>>
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\vector(751): note: see reference to function template instantiation 'std::thread *std::vector<std::thread,std::allocator<_Ty>>::_Ucopy<std::_Vector_const_iterator<std::_Vector_val<std::_Simple_types<std::thread>>>>(_Iter,_Iter,std::thread *)' being compiled
1> with
1> [
1> _Ty=std::thread,
1> _Iter=std::_Vector_const_iterator<std::_Vector_val<std::_Simple_types<std::thread>>>
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\vector(751): note: see reference to function template instantiation 'std::thread *std::vector<std::thread,std::allocator<_Ty>>::_Ucopy<std::_Vector_const_iterator<std::_Vector_val<std::_Simple_types<std::thread>>>>(_Iter,_Iter,std::thread *)' being compiled
1> with
1> [
1> _Ty=std::thread,
1> _Iter=std::_Vector_const_iterator<std::_Vector_val<std::_Simple_types<std::thread>>>
1> ]
1> C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\include\vector(742): note: while compiling class template member function 'std::vector<std::thread,std::allocator<_Ty>>::vector(const std::vector<_Ty,std::allocator<_Ty>> &)'
1> with
1> [
1> _Ty=std::thread
1> ]
我无法立即看到问题，因为它在gcc上可以正常工作。我怀疑编译器没有调用适当的push_back重载。
我会尝试改用emplace。
threads.emplace_back( [=,&fn]()
{
for ( int j = from; j < to; ++j )
fn( j );
} );
编辑：由于显然编译器也不支持emplace，我可能会退回到std::vector<std::shared_ptr<std::thread> >，并将插入代码更改为
threads.emplace_back( std::make_shared<std::thread>( [=,&fn]()
{
for ( int j = from; j < to; ++j )
fn( j );
} ) );
连接循环也必须进行更改。
本文收集自互联网，转载请注明来源。
如有侵权，请联系 [email protected] 删除。
我来说两句