cleanup a->w cross calls in advapi32/crypt.c

Shachar Shemesh wine-devel at
Mon Aug 2 23:55:51 CDT 2004

James Hawkins wrote:

>>-             strcpy(keyname + strlen(KEYSTR), pProvName);
>I changed that line to strcatW(keyname, pProvName).  That makes a lot
>more sense Mike, thanks for the tip.
>I'm wasn't exactly sure on this one so it would be great if you could
>help me on this one.  When using pointer arithmetic, do the operations
>such as --, ++... increment or decrement by the size of the pointer
>type?  For example,
>*(ptr - sizeof(WCHAR)) = (dwType % 10) + '0';
>*(ptr - sizeof(WCHAR) * 2) = ((dwType / 10) % 10) + '0';
>*(ptr - sizeof(WCHAR) * 3) = (dwType / 100) + '0';
>Is the sizeof(WCHAR) multiplication redundant because --ptr actually
>moves ptr down one WCHAR?  I understand that if that's the case, but
>what about when the pointer is first initialized?
>ptr = keyname + strlenW(keyname);
>I guess it holds true here as well because keyname is a pointer and
>we're adding ot it.  If that is the case, the included patch fixes the
>two things mentioned.
Ok, whenever such matters come up, it's always wise to go to the source 
and ask the most authorative book there is. This is what the bible has 
to say about this (bible = "The C Programing Language, 2nd edition"):
Page 98 bottom:
"These remarks are true regardless of the type or size of the variables 
in the array a. The meaning of "adding 1 to a pointer," and by 
extension, all pointer arithmetics, is that pa+1 points to the next 
object, and pa+i points to the i-th object beyond pa."

In other words, ANY time you add or subtract and integer from a pointer, 
the result is to move the pointer to another array element. No need to 
perform these "word size" calculations anywhere.

Question: Did you compile and check you patch?


Shachar Shemesh
Lingnu Open Source Consulting ltd.

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