Bourne shell differences w.r.t functions?

[Erik E. Rantapaa]

In experimenting on various systems, I have found the following
differences in the way /bin/sh handles functions:

   * Some give functions their own private argument list.
   * Some have arguments passed to functions overwrite the script's
     argument list.
   * Some don't support functions at all.

I have some questions that maybe the net could help with:

If /bin/sh supports functions, which behavior is more common?

Also, does the fact that some Bourne shells don't support functions
mean that I shouldn't use functions in scripts which I send out for
general use?  Are replacements such as bash and ksh widely enough
available so people can use them if they have a defective /bin/sh?

For maximum portability, should I just avoid using functions
altogether? :(

Finally, what is the POSIX standard with regard to this?
-- 
Erik Rantapaa
  rantapaa at cs.umn.edu