Obsolescent character function (Cygwin)

[Brooks Moses]

Angelo Graziosi wrote:
> When I build the following simple test case 
[...]
> I have:
> 
> -------------------------------------
>  In file prova.F95:8
> 
> function chfun(x)
>              1
> Warning: CHARACTER(*) function 'chfun' at (1) is obsolescent in fortran 95
> 
> --------------------------------------
> 
> Why is 'chfun' obsolescent ?

Because it has a return value that is declared as an assumed-length 
character string, and the Fortran 95 Language Standard states that 
functions with assumed-length character return values are an obsolecent 
feature of the language.

The standard states that features are declared to be obsolescent only 
when better methods for achieving the same functionality exist (and 
existed in the previous standard as well), and when "it is recommended 
that programmers should use these better methods in new programs and 
convert existing code to these methods."

One possible rewriting of your code would be to pass the result length 
in as an argument:

--------------------------------------------
program prova
   implicit none
   character(len = 10) :: chfun

   write(*,*) chfun(5),chfun(25)

contains
   function chfun(x,n)
     integer :: x,n
     character(len=n) :: chfun

     write(chfun,'(I10)')  x
   end function chfun
end program prova
--------------------------------------------

Note that this change does require that the program have an "explicit 
interface" for chfun.  The easiest way to accomplish that is containing 
chfun within the main program as I've done, but you could also put chfun 
in a module that's used within the main program, or declare an interface 
block to it within the main program.

- Brooks