Re: #define....

Hi Robert,

I am seeing this in many example programs of the "Programming Microsoft
Windows CE .NET" book where the following define statement appears at the top
of their header file examples.

#define dim(x) (sizeof(x) / sizeof(x[0]))

I am trying to understand what this line has to do with the rest of the
code. If anyone has this book (Isbn# 0-7356-1884-4) the ex. starts on P.18.

The way I see this is that we are dividing the size of x by the size of x[0]
and defining this by Dim(x). IM LOST!


because you must use Unicode under Windows CE, a lot of code looks like this:

TCHAR szText[128];
GetWindowText(hwnd, szText, sizeof(szText)/sizeof(TCHAR));
LoadString(hInst, IDS_STRING, szText, sizeof(szText)/sizeof(TCHAR));

So defining the very handy macro above will reduce the code to this:

TCHAR szText[128];
GetWindowText(hwnd, szText, dim(szText));
LoadString(hInst, IDS_STRING, dim(szText));

#define DIMOF(X) (sizeof(X) / sizeof(X[0]))
is a universal form of
#define CHAROF(X) ((X) / sizeof(TCHAR))

Another handy macro is:
#define CBTEXT(X) ((X) * sizeof(TCHAR))
for allocating memory:

TCHAR *psz
cch = _tcslen(pszSrc);
psz = malloc(CBTEXT(cch+1));
_tcscpy(pszDest, pszSrc);

Therefore it is a good idea, defining these macros in every source file.

Regards Wolfgang
.

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