Re: C23 thoughts and opinions

On 24/05/2024 16:45, Keith Thompson wrote:

Thiago Adams <thiago.adams@gmail.com> writes:

On 23/05/2024 18:49, Keith Thompson wrote:

error: 'constexpr' pointer initializer is not null
5 |     constexpr char * s[] = {"a", "b"};
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Then we were asking why constexpr was used in that case.

Why not?

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When I see a constexpr I ask if the compiler is able to compute
everything at compile time. If not immediately it is a bad usage in my
view.

 I don't understand.  Do you object because it's not *immediately
obvious* that everthing can be computed at compile time?  If so, why
should it have to be?

My understanding is that constexpr is a tip for the compiler. Does not ensure anything. Unless you use where constant expression is required.
So I don't like to see constexpr  where I know it is not a constant expression.
C++ has consteval (https://en.cppreference.com/w/cpp/language/consteval) . When I first saw it I thought it was a joke.
"every potentially-evaluated call to the function must (directly or indirectly) produce a compile time constant expression. "
Also  constinit
https://en.cppreference.com/w/cpp/language/constinit
I never used these features I want never want to use. It is a total mess in my opinion.

If nothing else, the fact that the code compiles should be proof enough.
You said something upthread about the compiler ignoring constexpr if the
expression isn't compile-time evaluable; perhaps you were using a buggy
compiler?
 Note that the above code is C++, not C, and that it should be "constexpr
const char *".
 

I may have to implement constexpr in cake... So at some point I will see all details.