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functionaility of macros

1
#define LOWORD(l) ((WORD)(l))
#define HIWORD(l) ((WORD)(((DWORD)(l) >> 16) & 0xFFFF))

Explain functionality of both of these macros
May 8 '10 #1
3 1346
weaknessforcats
9,208 Expert Mod 8TB
I can't do any better than a Google of HIWORD and LOWORD.

Keep in mind that these are very old Windows macros back when 16-bit machines were the latest thing.

I personally have never used this thing.
May 8 '10 #2
Banfa
9,065 Expert Mod 8TB
Hmmm actually I think you will find that these macros are actually part of the WIN32 API for 32 bit machines. Quite useful for decoding such things and the wParam of WM_COMMAND and other message parameters where often 2 16bit parameters were carried in a single 32bit value.
May 8 '10 #3
donbock
2,426 Expert 2GB
Personally, I would have defined LOWORD differently:
Expand|Select|Wrap|Line Numbers
  1. #define LOWORD(I) ((WORD)((I) & 0xFFFF))
I prefer explicit masking to relying on overflow to work the way you expect.
May 10 '10 #4

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