Re: question about linker

On 01/12/2024 17:57, Michael S wrote:

On Sun, 1 Dec 2024 15:34:04 +0100
David Brown <david.brown@hesbynett.no> wrote:

>
I can see some advantages in a language being happy with any order of
function definition, without requiring forward declarations to use a
function before it is defined.  But C is not like that, and I cannot
honestly say it bothers me one way or the other.  And apparently, it
does not particularly bother many people - there is, I think, no
serious impediment or backwards compatibility issue that would
prevent C being changed in this way.  Yet no one has felt the need
for it - at least not strongly enough to fight for it going in the
standard or being a common compiler extension.
>
>
>

 I think, arguing in favor of such change would be easier on top of
the changes made in C23.
Before C23 there were, as you put it "no serious impediment or
backwards compatibility issue". After C23 we could more categorical
claim that there are no new issues.
 

Does that mean there was something that you think was allowed in C before C23, but not after C23, that would potentially be a problem here?
What, specifically, are you thinking of?
The changes in declarations in C23, AFAIK, are that "void foo();" now means the same as "void foo(void);", and that in general non-prototype function declarations are no longer allowed.  (That is a good change, of course - 30 years late, but still welcome.)  But I can't think of a situation where code that is correct under the current "declare before using" rule would no longer be correct if "declare before or after" were allowed at the file-scope level.
Maybe you could construct something by playing silly-buggers with macros to re-define identifiers at different points in the code.
I can't say I've thought much about the consequences of such a rule change - it doesn't seem a realistic change to me, and I have no problem with the current rule.  So it's quite possible that I've missed something.