Shell out bug in pg (but a more general problem)

Mike Leibensperger leiby at masscomp.UUCP
Tue Mar 12 11:30:27 AEST 1985


In article <562 at rlgvax.UUCP> guy at rlgvax.UUCP (Guy Harris) writes:
>Code which starts up a child process and does a general "wait" for any
>children without checking that the child they're interested in is what
>exited is broken, due, as you mentioned, to the fact that the shell's
>way of setting up pipelines creates unexpected edges in the family
>tree of processes.

Does anyone know what the rational was/is for having the shell create
pipelines in this seemingly ludicrous way (i.e. the Nth process in the
pipeline is parent of the (N-1)st)?  After all, why should a program 
need to concern itself with the process behaviour of previous programs 
in its pipeline?  It just rubs me the wrong way.

If someone could enlighten me about the rational for this change, and
about when the change first appeared, I would appreciate it.  The 'r'
key is sufficient....
--
Mike Leibensperger
Masscomp; 1 Technology Park; Westford, MA 01886
{decvax,harpo,tektronix}!masscomp!leiby



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