[Bug fortran/45466] Bus Error: C program calls Fortran Function which has returned value as Character string

["Lulin dot Song at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #9 from Lulin dot Song at gmail dot com  2010-09-01 14:22 -------
(In reply to comment #8)
> (In reply to comment #0)
> > Main program is written in C. (see the following)
> 
> I strongly suggest using the C Binding facility of Fortran 2003 instead of
> relying on the internals of a given compiler. GCC/gfortran supports the C
> binding since 4.3.0 and newer version of most other compilers support it as
> well.
> 
> Cf. http://gcc.gnu.org/onlinedocs/gfortran/Interoperability-with-C.html
> 
> The article at
> http://www.fortranplus.co.uk/resource/fortran_2003_2008_compiler_support.pdf
> lists for some compilers the support of Fortran 2003 (and 2008) features;
> interesting for you are the items "Interoperability with C". Note: The list is
> incomplete as not all vendors have submitted their data.

Thank you all for the information and suggestions. Fortran2003 C Binding
facility seems to be what we should do next. Our project is a large
Fortran77,90,95 C mixing language software been developed for years. It is hard
to make it work with three different compilers (Intel ifort, AbfSalford ftn95
and gfortran).

> 
> Regarding GCC/gfortran 4.1: I have no idea why it worked for you, but the
> calling convention of 4.1 was the same (I just checked).
> 
It is mystery to me too. The small program I submitted here works if compiled
with 4.1.2 .

Another curious thought. 

When the return value is integer or double, the dump looks like

requestdouble (real(kind=8) & rlat, real(kind=8) & rlng)

when the return value is character string, is it more intuitive to be

 requestdouble ( real(kind=8) & rlat, real(kind=8) &
rlng,character(kind=1)[1:16] & __result, integer(kind=4) .__result)

instead of

requestdouble (character(kind=1)[1:16] & __result, integer(kind=4) .__result   
, real(kind=8) & rlat, real(kind=8) & rlng) ?

I mean the ".__result" appending to arguments list instead inserting before
arguments list.

Many thanks again.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45466