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From: Bart <bc@freeuk.com>
Newsgroups: comp.lang.c
Subject: Re: else ladders practice
Date: Thu, 7 Nov 2024 15:08:34 +0000
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On 07/11/2024 12:23, Bart wrote:
> On 06/11/2024 14:50, David Brown wrote:

>> C gets it right here.  There is no need for a return type when there 
>> is no return
> 
> There is no return for only half the function! A function with a return 
> type is a function that CAN return. If it can't ever return, then make 
> it a procedure.
> 
> Take this function where N can never be zero; is this the right way to 
> write it in C:
> 
>     int F(int N) {
>         if (N==0) unreachable();
>         return abc/N;              // abc is a global with value 100
>     }
> 
> If doesn't look right. If I compile it with gcc (using 
> __builtin_unreachable), and call F(0), then it crashes. So it doesn't do 
> much does it?!

It looks like it needs 'else' here. If I put that in, then F(0) returns 
either 0 or 1, so it returns garbage, whether or not 'unreachable' is 
used in the branch.

So I'm struggling to see the point of it. Is it just to quieten the 
'reaches end of non-void function' warning when used before the final '}'?

In any case, 'unreachable' is a misnomer. 'shouldnt_be_reachable' is 
more accurate.