Re: creating dll to link with delphi program

[Steve Kargl <sgk at troutmask dot apl dot washington dot edu>]

On Sun, Oct 23, 2011 at 11:07:09AM -0700, Brad Finney wrote:
> 
> 
> On 10/23/2011 7:18 AM, Tobias Burnus wrote:
> >Brad Finney wrote:
> >>SUBROUTINE PrintOutX(x)
> >>!GCC$ ATTRIBUTES DLLEXPORT::PrintOutX
> >>write(*,*)x
> >>END SUBROUTINE PrintOutX
> >>
> >>if I use
> >>gfortran -c -fno-leading-underscore -fno-underscoring testcase.f90
> >>
> >>The object file contains -export:"printoutx" which does not preserve
> >>the case of the requested export name.
> >
> >In gfortran - contrary to ifort -, you have to use C binding, cf.
> >http://gcc.gnu.org/onlinedocs/gfortran/Mixed_002dLanguage-Programming.html
> >
> >SUBROUTINE PrintOutX(x) bind(c, name="PrintOutX")
> >!GCC$ ATTRIBUTES DLLEXPORT::PrintOutX
> >use iso_c_binding
> >real(c_float) x
> >write(*,*) x
> >end
> >
> >
> >That should work without special options. Note: Depending on the caller,
> >you might need to add "stdcall" - but the default "cdecl" could also be
> >correct.
> >
> >Tobias
> >
> 
> 
> I guess I did not make myself clear enough with my example.  The problem 
> is not with the argument x, it is with the leading and trailing 
> underscores added to the procedure names.  If I use
> 
> -fno-leading-underscore
> 
> then the object code contains references to gfortran library routines 
> without the additional underscore and the linker can't resolve those 
> references.  If I don't use the -fno-leading-underscore option, then my 
> procedure names have a leading underscore which the previously compiled 
> main program can't find since it is looking for names lacking the 
> leading underscore.
> 
> What I need is a way to turn off leading (and trailing) underscores for 
> my routines but not gfortran library routine names.  I am also concerned 
> that gfortran does not seem to be preserving the case of the requested 
> exported procedure names.

Did you try Tobias's suggestion

laptop:kargl[213] cat foo.f90
subroutine foo(n) bind(c, name="Foo")
  use iso_c_binding
  integer(c_int) :: n
  n = n + n
end subroutine foo

subroutine bar(n)
  use iso_c_binding
  integer(c_int) :: n
  n = n + n
end subroutine bar
laptop:kargl[214] gfc4x -c foo.f90
laptop:kargl[215] nm foo.o
00000000 T Foo
00000016 T bar_

foo and bar are identical except for explicitly namng foo
as Foo in the bind() expression.  Note case is preserved and
there is no trailing underscore.

-- 
Steve