
“That is either genius, or a seriously diseased mind.” – Linus Torvalds - sooham
https://lkml.org/lkml/2018/3/20/845
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roelschroeven
In that post Linus says something I don't understand in that post:

"... So with a constant, we have

    
    
      sizeof( 1 ? NULL : (int *) 1)
      

and the rule is that if one of the sides of a ternary operation with pointers
is NULL, the end result is the other type (int *)."

Is Linus saying that the condition of the ternary operation doesn't matter if
one of the sides is NULL? That it then always evaluates to the other side?
That's not what happens when I try it. Or are there special rules when sizeof
is applied?

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roelschroeven
Oh, I get it now: Linus wasn't talking about the values, but about the types.
In this case, the result will be a NULL pointer of type (int *).

Sorry, nothing to see here.

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cbsks
I just had the same confusion. Thanks for figuring it out so I didn’t have to!

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rurban
I really need this for libc optimizations. So far it only worked in C++ mode
or newer clang's, but not in gcc.

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msarnoff
Isn't this what GCC's `__builtin_constant_p()` does?

