exit code of program filtering headers

I'm interested in the exit code of a grep -f patternfile run over all
the headers. However, I don't want the original msg changed. The first
two things which spring to mind

   :0
   * ? grep -f 

and

   :0 fhw
   | grep -f 

don't work because the first doesn't get to see the headers, and the
second removes all headers not matching something in patternfile.

A functional solution seems to be

  :0 c:
  tmp.$$
  :0
  * ? grep -if patternfile tmp.$$
  { ... }
  t=`rm -f tmp.$$`

but is there a solution which doesn't use a tmp file, or a specially
crafted external program?

Thanks,

Volker

-- 
Volker Kuhlmann                 is possibly list0570 with the domain in header
http://volker.dnsalias.net/             Please do not CC list postings to me.

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