Messages in this thread | | | Date | Thu, 09 Oct 2008 13:57:32 -0700 | From | "H. Peter Anvin" <> | Subject | Re: dup2() vs dup3() inconsistency when |
| |
Ulrich Drepper wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > H. Peter Anvin wrote: >> The result of dup3(fd, fd, O_CLOEXEC) is to set the O_CLOEXEC flag on fd. > > That's bad and disregarded by Al and myself because it is one and the > same descriptor and therefore it changes the source descriptor.
It's not the source descriptor, per se, it is the "new" descriptor, which happens to have a side effect of closing the "old" descriptor.
>> Step (2) could be considered a bit dubious, but the behaviour of >> dup2(fd, fd) is a direct consequence of the chosen semantics. > > The behavior of dup2(fd,fd) is just a result of an accident in the > original implementation. It makes no sense and the mistake doesn't have > to be repeated.
Inconsistency is bad, too, and one could *definitely* argue that the fundamental problem is the one of closing a pre-existing descriptor rather than forcing the user to do that explicitly if that behaviour was desired.
-hpa
| |