使用mem_fun_ref与升压:: shared_ptr的 [英] Using mem_fun_ref with boost::shared_ptr

问题描述

页面的建议，我试图让shared_ptr的调用的IUnknown ::发布（），而不是删除：

  IDirectDrawSurface * DDS;
... //分配DDS
返回的shared_ptr＆LT; IDirectDrawSurface＆GT;（DDS，mem_fun_ref（安培;的IUnknown ::释放））;
 

  

错误C2784：'的std :: const_mem_fun1_ref_t＆LT; _result，_Ty，_Arg>的std :: mem_fun_ref（结果（的_thiscall _Ty :: *）（_精氨酸）常量）：无法推断出模板参数对于'的结果（的_thiscall _Ty :: *）（精氨酸）常量'从'ULONG（的_cdecl的IUnknown :: *）（无效）

  
  

错误C2784：'的std :: const_mem_fun_ref_t＆LT; _result，_Ty>的std :: mem_fun_ref（结果（的_thiscall _Ty :: *）（无效）常量）：不能推导出模板参数为'的结果（的_thiscall _Ty :: *）从'ULONG（无效）常量（__cdecl的IUnknown :: *）（无效）

  
  

错误C2784：'的std :: mem_fun1_ref_t＆LT; _result，_Ty，_Arg>的std :: mem_fun_ref（结果（的_thiscall _Ty :: *）（_ ARG））：不能推导出模板参数为'的结果（的_thiscall _Ty :: *）（ ARG）'从'ULONG（的_cdecl的IUnknown :: *）（无效）

  
  

错误C2784：'的std :: mem_fun_ref_t＆LT; _result，_Ty>的std :: mem_fun_ref（结果（的_thiscall _Ty :: *）（无效））：不能推导出模板参数为结果（的_thiscall _Ty :: *）从'ULONG（无效）（__cdecl的IUnknown :: *）（无效）

  
  

错误C2661：提高:: shared_ptr的:: shared_ptr的'：没有重载函数需要两个参数

我不知道做这个东西。我有限的模板/仿函数知识使我试试

 的typedef ULONG（的IUnknown :: * releaseSignature）（无效）;
shared_ptr的＆LT; IDirectDrawSurface＆GT;（DDS，mem_fun_ref（的static_cast＆LT; releaseSignature＆GT;（安培;的IUnknown ::释放）））;
 

但无济于事。任何想法？

解决方案

不是调用约定说明问题吗？这是否OK？

 无效iUnk_delete（的IUnknown * U）{
  U-＆GT;发行（）;
}
返回的shared_ptr＆LT; IDirectDrawSurface＆GT;（DDS，iUnk_delete）;
 

Following the advice of this page, I'm trying to get shared_ptr to call IUnknown::Release() instead of delete:

IDirectDrawSurface* dds;
... //Allocate dds
return shared_ptr<IDirectDrawSurface>(dds, mem_fun_ref(&IUnknown::Release));

error C2784: 'std::const_mem_fun1_ref_t<_Result,_Ty,_Arg> std::mem_fun_ref(Result (_thiscall _Ty::* )(_Arg) const)' : could not deduce template argument for 'Result (_thiscall _Ty::* )(Arg) const' from 'ULONG (_cdecl IUnknown::* )(void)'

error C2784: 'std::const_mem_fun_ref_t<_Result,_Ty> std::mem_fun_ref(Result (_thiscall _Ty::* )(void) const)' : could not deduce template argument for 'Result (_thiscall _Ty::* )(void) const' from 'ULONG (__cdecl IUnknown::* )(void)'

error C2784: 'std::mem_fun1_ref_t<_Result,_Ty,_Arg> std::mem_fun_ref(Result (_thiscall _Ty::* )(_Arg))' : could not deduce template argument for 'Result (_thiscall _Ty::* )(Arg)' from 'ULONG (_cdecl IUnknown::* )(void)'

error C2784: 'std::mem_fun_ref_t<_Result,_Ty> std::mem_fun_ref(Result (_thiscall _Ty::* )(void))' : could not deduce template argument for 'Result (_thiscall _Ty::* )(void)' from 'ULONG (__cdecl IUnknown::* )(void)'

error C2661: 'boost::shared_ptr::shared_ptr' : no overloaded function takes 2 arguments

I have no idea what to make of this. My limited template/functor knowledge led me to try

typedef ULONG (IUnknown::*releaseSignature)(void);
shared_ptr<IDirectDrawSurface>(dds, mem_fun_ref(static_cast<releaseSignature>(&IUnknown::Release)));

But to no avail. Any ideas?

解决方案

Isn't the calling convention specifier a problem? Would this be OK?

void iUnk_delete(IUnknown* u) {
  u->Release();
}


return shared_ptr<IDirectDrawSurface>(dds, iUnk_delete);

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