Fortran compilation bug

[Michel Busquet (Forn_Natl) <busquet@this.nrl.navy.mil>]

The following source file produce an error at compilation time about 
alleged "undefined length" string

Source file:
----------------
         program a
         character ch*10
         ch='abcd'
         call b(ch)
         stop
         end
c
         subroutine b(ch)
         character ch*(*)
         integer i,l
         do i=1,len(ch)
          l=i
          if(ch(i:i).eq.' ') goto 1
         enddo
1       call C(ch(1:l)//'ok')
         return
         end
c
         subroutine C(ch)
         print *,ch
         return
         end


Compilation command line and messages :
-----------------------------------------------------------
$ g77 -o a.out a.f
a.f: In subroutine `b':
a.f:15:
    1       call C(ch(1:l)//'ok')
                   1      2
Concatenation operator at (2) must operate on two scalar (not array) 
subexpressions, two function invocations returning character scalars, 
or a combination of both -- but the subexpression at (1) is of 
indeterminate length
a.f: In subroutine `c':
a.f:15: warning:
    1       call C(ch(1:l)//'ok')
                 1
a.f:19: (continued):
            subroutine C(ch)
                       2
Argument #1 (named `ch') of `c' is one type at (2) but is some other 
type at (1) [info -f g77 M GLOBALS]



Gcc Version:
-----------------
gcc -v
Reading specs from /usr/libexec/gcc/darwin/ppc/3.3/specs
Thread model: posix
gcc version 3.3 20030304 (Apple Computer, Inc. build 1495)

Platform and system:
----------------------------
iMac + Mac OS X 10.3