Ben Bacarisse <ben.usenet@bsb.me.uk> writes:
> Kaz Kylheku <864-117-4973@kylheku.com> writes:
>> On 2022-11-01, Muttley@dastardlyhq.com <Muttley@dastardlyhq.com> wrote:
>>> Just found what happened. I'm developing my code simultaniously on Linux and
>>> MacOS and on MacOS with clang, if you don't #include <unistd.h> then any
>>> call to crypt() will return a bad (but non null) pointer no matter what the
>>> input parameters which then caused a crash later on.
>>
>> If you dohn't declare crypt, an implicit declaration of it will be
>> used, which is incorrect: int crypt(char *, char *).
>
> I think the implicit declaration would be int crypt() or, more
> accurately, just crypt() with an implicit int return type.

In C90, a call with two char* arguments would result in code that
assumes crypt() has two char* parameters (which it does) and returns an
int (which it doesn't, so the behavior is undefined). No diagnostic was
required.

C99 dropped the implicit int rule, so such a call is a constraint
violation with no specified behavior, but most compilers retain the C90
behavior. And most C compilers do not fully conform to any version
of the standard unless you ask them nicely.

--
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
Working, but not speaking, for XCOM Labs
void Void(void) { Void(); } /* The recursive call of the void */

On 01 Nov 2022 17:43:20 GMT
Nicolas George <nicolas$george@salle-s.org> wrote:
>Muttley@dastardlyhq.com, dans le message <tjrjj3$j4a$1@gioia.aioe.org>,
> a �crit�:
>> I was. I didn't spot it as its a work in progress which still has warnings.
>
>I do not think fixing the warnings at the end is a winning strategy.

Thanks for the heads up. Its a large program and I was concentrating on
another module.