dup2() vs dup3() inconsistency when

From: Michael Kerrisk
Date: Thu Oct 09 2008 - 08:10:25 EST


Al,

your 2008-07-26 commit 6c5d0512a091480c9f981162227fdb1c9d70e555 for
fs/fcntl.c:sys_dup3 contains

+ if (unlikely(oldfd == newfd))
+ return -EINVAL;

This makes dup2() and dup3() differ with respect to the oldfd==newfd
case (dup2() becomes a no-op, just returning oldfd, dup3() gives the
EINVAL error.

Your commit log doesn't explain the rationale for this change. What
is it? (I could guess that it is to error on a case that may be a
user programming error, but I want to check this with you, so that I
add the right text to the man page.)

Cheers,

Michael


--
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
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