Re: Loops (was Re: do { quit; } else { })

On 12/05/2025 22:38, Keith Thompson wrote:

David Brown <david.brown@hesbynett.no> writes:
[...]

I am not convinced that it is actually useful as an error checking
mechanism in many situations.  In a lot of code, you simply don't have
a compile-time checkable array sizes - you have a pointer, and a
run-time variable for the size.  When you are calling your function
with a "static" array size, the compiler does not have any way to
check your pointer for correctness.

[...]
 Using [static N] in an array parameter declaration also requires the
caller to pass a non-NULL pointer.  If I want to tell the compiler
that an argument must not be a NULL pointer, I can write:
      void func(int arg[static 1]);
 func(NULL) then has undefined behavior, and a compiler is likely
to warn about it.  (Of course some UB will be missed if the compiler
can't detect it.)
 

Certainly compilers are more likely to be able to differentiate between null values and non-null values, than between pointers to different lengths of data.  So yes, this can be a useful check.
For my own use, I dislike this syntax - if I want a pointer to an int, I prefer to give the parameter the form pointer to an int.  The array form might mean the same thing to the compiler, but it does not give the same clarity to the human programmer.  And if I want extra checking on this kind of thing, I use gcc attributes.  (Of course not all programmers can do that, or want to do that, in their code.)