Re: Two questions on arrays with size defined by variables

On 09.02.2025 18:57, Michael S wrote:

On Sun, 9 Feb 2025 18:18:04 +0100
Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
 

On 09.02.2025 11:39, Michael S wrote:

On Sun, 9 Feb 2025 10:54:36 +0100
Janis Papanagnou <janis_papanagnou+ng@hotmail.com> wrote:
[...]
>
There is another problem in your code - it assigns string literal to
non-const char*. It is legal, as far as 'C' Standard is concerned,
but makes very little practical sense, because any attempt to
assign to string literal through resulting pointer is UB. And not
just a theoretical UB, but a real-world UB. 

>
This comment specifically draw my attention and made me nervous.
>
You know, I'm rarely programming in plain "C", and while in C++
I generally try to program in "const-correct" form

 
Which, I suppose, is not easy.

Well, if you start with it there seems to be no end. But once you
understand and got used to it it's like code patterns you apply
without thinking.

 

I never make
use of 'const' in "C". - Unless the compiler complains about it,
but I don't recall it (ever?) did.
>
In my test application I actually never assign string literals
or strings to any other string object (modulo the buffer that I
filled with a 'fgets'). I operate solely with pointers to 'argv'
elements and to the 'char buf[]' buffer data.
>
Do you see any issue with that?
>
Janis
>

 
I see no issues.

Good to hear.

 
Generally, due to absence of user-defined polymorphism, C does not have
the type of ugly surprises with constness that make life of C++
programmers miserable. Still, behavior of string literals can be
surprising.

Actually I think there's a lot that can surprise the unwary in "C". :-)

As "simple" as it is, I wouldn't classify it as an "easy" language
(i.e. it's not one that prevents you from making mistakes).

I would guess that if it was feasible to make a breaking changes, C89
would define type of string literals as 'const char*' rather than
'char*'. But breaking changes were not feasible.

Janis