c++ - 线程新手:在线程参数中使用 std::ref() 的问题

Question

我是 C++ 线程的新手，我正在尝试使打包在 std::vector 中的多个对象异步调用它们的 prepareForRendering(...) 方法。看来我错误地使用了 std::ref 。这有效:

for (ObjMesh& mesh : this->meshes) {

    // Prepare mesh
    std::thread t(&ObjMesh::prepareForRendering, mesh, pDevice, prepareTextures, prepareVertices, prepareBuffers, filter, addressMode);
    t.join();
}

这不是:

for (ObjMesh& mesh : this->meshes) {

    // Prepare mesh
    std::thread t(&ObjMesh::prepareForRendering, std::ref(mesh), pDevice, prepareTextures, prepareVertices, prepareBuffers, filter, addressMode);
    t.join();
}

编译器抛出:

1>c:\program files (x86)\microsoft visual studio 14.0\vc\include\thr\xthread(238): error C2893: Failed to specialize function template 'unknown-type std::invoke(_Callable &&,_Types &&...)'
1>  c:\program files (x86)\microsoft visual studio 14.0\vc\include\thr\xthread(238): note: With the following template arguments:
1>  c:\program files (x86)\microsoft visual studio 14.0\vc\include\thr\xthread(238): note: '_Callable=bool (__thiscall ObjMesh::* )(ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE)'
1>  c:\program files (x86)\microsoft visual studio 14.0\vc\include\thr\xthread(238): note: '_Types={std::reference_wrapper<ObjMesh>, ID3D11Device *, bool, bool, bool, D3D11_FILTER, D3D11_TEXTURE_ADDRESS_MODE}'
1>  c:\program files (x86)\microsoft visual studio 14.0\vc\include\thr\xthread(247): note: see reference to function template instantiation 'void std::_LaunchPad<_Target>::_Execute<0,1,2,3,4,5,6,7>(std::tuple<bool (__thiscall ObjMesh::* )(ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE),std::reference_wrapper<ObjMesh>,ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE> &,std::integer_sequence<_Ty,0,1,2,3,4,5,6,7>)' being compiled
1>          with
1>          [
1>              _Target=std::unique_ptr<std::tuple<bool (__thiscall ObjMesh::* )(ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE),std::reference_wrapper<ObjMesh>,ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE>,std::default_delete<std::tuple<bool (__thiscall ObjMesh::* )(ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE),std::reference_wrapper<ObjMesh>,ID3D11Device *,bool,bool,bool,D3D11_FILTER,D3D11_TEXTURE_ADDRESS_MODE>>>,
1>              _Ty=size_t
1>          ]

我需要确保 ObjMesh 实例在线程内通过引用传递。

(我知道我的线程模型毫无意义 - 这是一个例子)。 TYVM。

编辑准备渲染函数。

bool ObjMesh::prepareForRendering(ID3D11Device* pDevice, bool prepareTextures,  bool prepareVertices, bool prepareBuffers, D3D11_FILTER filter, D3D11_TEXTURE_ADDRESS_MODE addressMode);

Answer 1

只需将指针传递给绑定(bind):

std::thread t(&ObjMesh::prepareForRendering, &mesh, pDevice, prepareTextures, prepareVertices, prepareBuffers, filter, addressMode);