sizeof(long) in 64-bit C++

Question

I have downloaded MinGW-64, so I can now compile 64-bit programs for Windows 7, using g++ 4.7.0 (experimental). But the following line:

cout << sizeof(         


        

Answer 1

MinGW is designed to build a WIN32 application and WIN32 headers/libraries assumes the long(or LONG) type to be 32 bits wide even on a 64bit Windows. Microsoft decided that otherwise so much of the existing Windows source codes should be changed. For example, the following structure uses LONG types.

typedef struct tagBITMAPINFOHEADER { 
...
  LONG biWidth; 
  LONG biHeight; 
...
} BITMAPINFOHEADER

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