[Bug fortran/90329] Incompatibility between gfortran and C lapack calls

[tkoenig at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90329

--- Comment #6 from Thomas Koenig <tkoenig at gcc dot gnu.org> ---
(In reply to Janne Blomqvist from comment #5)
> (In reply to Thomas Koenig from comment #4)
> > Currently, I am leaning towards using an option with a mandatory
> > warning (no way to turn it off) which does not push any string lenghts
> > onto the stack at all, something like -fbroken-character-abi,
> > which we would use for external procedures without an explicit interface.
> 
> Hmm, wouldn't this completely break procedures with "character(len=*)" dummy
> arguments?

Yes :-(

This would be more or less equivalent to a -fbind-c flag.

>Or did mean that it would be used only for length=1 strings?

Unfortunately, the callee does not know the string length
passed by the caller.

> > I can also extend -fc-prototypes so that it also issues prototypes
> > for any global procedures outside of BIND(C), or add a new option.
> 
> This might be useful.

I just noticed that -fc-prototypes does not issue a prototype
for a global BIND(C) procedure. I'll probably fix that one soon.