委托构造函数C ++ [英] Delegate Constructor C++

问题描述

我这样做吗？我试图委托一个C ++类构造函数，因为它基本上是相同的代码重复3次。我读了C ++ x11和阅读g ++ 4.7.2允许这个，但我不知道如果我做的

Am I doing this right? I'm trying to delegate a C++ class constructor as it's basically the same code repeating 3 times.. I read up on C++x11 and read that g++ 4.7.2 allows this but I'm not sure if I'm doing it right:

Bitmap::Bitmap(HBITMAP Bmp)
{
   //Construct some bitmap stuff..
}

Bitmap::Bitmap(WORD ResourceID)
{
   HBITMAP BMP = (HBITMAP)LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(ResourceID), IMAGE_BITMAP, 0, 0, LR_SHARED);

   Bitmap(BMP);   //Delegates to the above constructor? Or does this create a temporary?
}

或者我需要做：

Bitmap::Bitmap(HBITMAP Bmp)
{
   //Construct some bitmap stuff..
}

Bitmap::Bitmap(WORD ResourceID) : Bitmap((HBITMAP)LoadImage(GetModuleHandle(NULL), MAKEINTRESOURCE(ResourceID), IMAGE_BITMAP, 0, 0, LR_SHARED))
{
}

推荐答案

委托构造函数只能在构造函数的初始化列表中工作，否则你只会创建一个临时的或者像你提到的其他错误。

You need to do the second. Delegating constructors only works in the constructor's initialization list, otherwise you'll just create a temporary or do other mistakes like you mentioned.

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