[m-users.] Change in compiler behaviour for 22.01.8 ? Pointer type strictness increased?

[Volker Wysk]

Am Samstag, dem 27.04.2024 um 11:06 +0200 schrieb Volker Wysk:
> Hi, Sean
> 
> Am Samstag, dem 27.04.2024 um 08:42 +0100 schrieb Sean Charles
> (emacstheviking):
> > Nope. 
> 
> Really? That's strange. I have this in the improved ODBC library:
> 
> :- pragma foreign_type("C", statement, "MODBC_Statement *",
>     [can_pass_as_mercury_type]).
> 
> And it works. 
> 
> But, this is the type of MR_copy_string:
> 
>     extern char *MR_copy_string(const char *s);
> 
> And you have:
> 
>     Files = MR_list_cons(MR_copy_string(dfl.paths[i]), Files);
> 
> MR_list_cons is a macro, which I can't see what it does, at the first go.
> But it seems like it requires an MR_Word as the first argument. Try this:
> 
>     Files = MR_list_cons((MR_Word) MR_copy_string(dfl.paths[i]), Files);
> 
> It seems like the C compiler is stricter than in the previous Mercury
> version, with respect to implicit type conversions. Perhaps someone has
> added a parameter for the call of gcc. The "-Wint-conversion" from your
> error messages could be it.

Hmm.. I've looked up -Wint-conversion from the GCC manual, and it says:

    Do not warn about incompatible integer to pointer and pointer to
    integer conversions.

So it should *not* generate this error. Maybe there's another GCC flag
that's responsible... I'd just try it with explicit casts.

On the other hand, maybe that mention in your error output is a hint to a
flag that's *not* being used. Maybe try to add it.

Cheers,
Volker