Re: dup2() vs dup3() inconsistency when

[Heikki Orsila]

On Thu, Oct 09, 2008 at 01:31:39PM -0700, Ulrich Drepper wrote:
> H. Peter Anvin wrote:
> > The dup2() behavior comes from the logical consequence of dup2()'s
> > "close on reuse"; one would think it would be logical for dup3() to
> > behave the same way.
> 
> No.  We deliberately decided on this change.  Otherwise, what is the
> result of dup3(fd, fd, O_CLOEXEC)?  There is no reason to use
> dup2(fd,fd), so why the hell somebody wants to defend this is beyond me.

The reason is: application programmers expect it to behave that way. 
The interface is mostly targeted for typical application programmers, 
and consistency decreases bugs. In this respect, it would be a good 
idea for dup3() to have the same semantics. Doing that might not make 
practical sense, but it is secondary to obviousness.

-- 
Heikki Orsila
heikki.orsila@xxxxxx
http://www.iki.fi/shd
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