Re: lib/45148: dup2(3) and dup3(3) should support EINVAL

[David Laight <david%l8s.co.uk@localhost>]

The following reply was made to PR lib/45148; it has been noted by GNATS.

From: David Laight <david%l8s.co.uk@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: lib/45148: dup2(3) and dup3(3) should support EINVAL
Date: Sun, 17 Jul 2011 09:48:40 +0100

 On Sun, Jul 17, 2011 at 03:25:02AM +0000, David Holland wrote:
 >  
 >  dup3 should be a superset of dup2, IOW, dup2(a, b) === dup3(a, b, 0).
 >  Anything else is insane and begging for bizarre problems in the future.
 
 Seems to me it should actually have the functionality of, dup(), dup2()
 and fcntl(F_DUPFD) - depending on the flags.
 
 So as well as O_CLOEXEC and O_NONBLOCK it needs a O_SCAN_FREE.
 
 Then:
   dup(nfd) == fcntl(nfd, F_DUPFD, 0)
   fcntl(nfd, F_DUPFD, ofd) == dup3(nfd, ofd, O_SCAN_FREE)
   dup2(nfd, ofd) == dup3(nfd, ofd, 0)
 
 Oh - and the man page really ought to include the fcntl() action.
 
        David
 
 -- 
 David Laight: david%l8s.co.uk@localhost