• C

Casting question

This question is about casting and
leading *:s

Does
  a_p = ***(void****)b_p
make sence ?
Is it the same as
  a_p = *(void****)b_p ???

/Confused
LVL 1
CrypToniCAsked:
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jkrConnect With a Mentor Commented:
>>Does
>> a_p = ***(void****)b_p
>>make sence ?

Yes, absolutely. I mean, if 'b_p' is of type 'void****', of course,

>Is it the same as
> a_p = *(void****)b_p ???

No, not at all - this makes 'a_p' an 'void***'
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BlackDiamondCommented:
CryptToniC,
jkr is absolutely correct.   I will elaborate a couple more examples that should hopefully make the derefrencing more clear.

void a_p = ****(void****)b_p
void * a_p = ***(void****)b_p
void ** a_p = **(void****)b_p
void *** a_p = *(void****)b_p
void **** a_p = (void****)b_p



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BlackDiamondCommented:
also, I only included the first line for clarity.  It is actually illegal to have a (void) variable (since it would have no context of size).  The way you would use the first line would be more like:

int a_p = (int)(****(void****)b_p)
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0xDEADBEEFCommented:
Hmmm... a void**** variable would indicate a 3d-array of pointers to void, so

void* a_p = ***(void****)b_p

would be the same as

void* a_p = b_p[0][0][0];

so a_p is a pointer to void, or, the contents of a slot.  But

void*** a_p = *(void***)b_p;

would equal

void*** a_p = b_p[0];

so a_p would be a pointer to a pointer to a pointer to void, or, a 2d-array of pointers to void.

Hope this helps, I know it's confusing.
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CrypToniCAuthor Commented:
jkr, was the first to answer so this seems fair

Hmm if one returns to basics the answer is often obvious :)

Not often I see code like this, Thanks alot
Regards CrypToniC
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