Re: RE: C99 questions about freopen(NULL, ...)

[David Korn <yyy@xxxxxxxxxxxxxxxx>]

> P.S.  There may be a weirdnix here; did we ever actually require that
> "(cat a; cat b)> foo" be the same as "cat a b > foo" or did this just
> fall so deeply into the "common sense" category that we never said it?
> (Obviously more generalized than here.)
> 
> 

This is required since cat a; cat b is a sequential list
and must produce a copy of a followed by a copy of b.
The () cause the sequential list to be executed in a subshell,
and the redirection causes the output to be redirected.
It has no affect on the output itself.

Thus unless otherwise specified by the semantics of foo,
        foo
and
        foo > file
produce the same output but differ only on where the output is
directed.

If compilation with c99 produces different results, the don't
compile with c99.  Also, note that there is no requirement that
stdio is used to implement any of the utilities.

David Korn
yyy@xxxxxxxxxxxxxxxx