command-line calls of GPL'd executables

[phil hunt]

Consider this situation:
 
Alice writes a program, aprog, which she licenses under the GPL.
 
Bob writes another program, which invokes the aprog executable,
using the POSIX system() call. Does Bob's program have to be
released under a GPL-compatible license?
 
(Assume for the sake of argument that there is no other program
that does the same as aprog).
 
What if aprog is, instead, licensed under the BSDL with advertising
clause. Can be GPL his program?    


-- 
#===== Philip Hunt == philh at comuno.freeserve.co.uk ======#
    Herbivore: effort-free public key encryption. See:
<http://www.vision25.demon.co.uk/oss/herbivore/intro.html>
        ** First software release coming soon! **