Re: Error in 'man operator'

[David Sletten <david.paul.sletten@gmail.com>]

Ha. Nice work.

On 8/27/21 8:17 PM, Alejandro Colomar (man-pages) wrote:
> Hi David,
>
> On 8/28/21 2:01 AM, Alejandro Colomar (man-pages) wrote:
>> I mean:
>> !(int)x
>> (int)!x
>>
>> The precedence doesn't matter there, as they apply one after the 
>> other, right to left.
>>
>> So, I'll keep casts in row 2.
>
> Hmm, I just came up with some very stupid piece of code that can show 
> the different precedence between "unary operators" and "cast operators":
>
> sizeof(int)x;
>
> Which I hope no-one on earth would ever want to be valid C.
>
> If casts had the same precedence as unary operators, this would be:
> First, cast x to int, then apply sizeof to the resulting int (since 
> sizeof can be used without parentheses on non-types).
>
> But since sizeof has greater precedence than the cast, it would be:
> First, calculate sizeof(int), then... x?  Invalid expression!
>
> And luckily, the second thing happens, and the compiler yells:
>
> sizeof.c: In function ‘foo’:
> sizeof.c:3:20: error: expected ‘;’ before ‘x’
>     3 |  return sizeof(int)x;
>       |                    ^
>       |                    ;
>
>
> So I think this deserves a new row.
>
> Thanks!
>
> Alex
>
>>
>> Cheers,
>>
>> Alex
>>
>
>
-- 
Have all good days!
David Sletten