Re: [9fans] void*

[adr <adr@SDF.ORG>]

On Sun, 15 May 2022, ori@eigenstate.org wrote:
>> On Sun, 15 May 2022, arnold@skeeve.com wrote:
>>
>>> It allows you pass pointers of any type without requiring casts:
>>>
>>>        struct foo s[5] = ...
>>>        memmove(s, & s[1], 4 * sizeof(struct foo));     // shift down 1
>>>
>>> The compiler won't complain because any pointer type can be passed
>>> to a void* parameter.  Otherwise you'd need to cast:
>>>
>>>        memmove((uchar*) s, (uchar*) & s[1], 4 * sizeof(struct foo));
>>
>> Sure, but you could change it to do the same with char*.
>>
>
> char* has legitimate uses for things other than generic pointers,
> and the conversion complaints catch bugs.

My point here is that It makes more sense to me to use a generic
pointer which have a size (the type it points) of 1, so arithmetic
can be applied to it. Of course I'm not proposing to change the
compiler and all the code. It was just a reflection. Allowing
arithmetic on void* solves the problem. Reading the definition of
void this could look incongruous, but C99 already specifies:

"A pointer to void shall have the same representation and alignment requirements as a
pointer to a character type"

So I don't see any real trouble to allow the same operations as with char*.

Again, just some thoughts. The comments about uchar* or uint8* are
because arithmetic on void* brakes the concept of void, I don't
really like it.  But sometime things are doomed to staid as they
are, even if they don't make sense...

adr.

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