-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 According to Ed Schouten on 1/18/2009 3:19 PM: > But that's not a proper fix anyway. cat can't just decide to reopen the > file descriptor of the standard output. That even breaks the first > sentence of POSIX: > > The cat utility shall read files in sequence and shall write > their contents to the standard output in the same sequence. > > If it says "the standard output" doesn't mean you can reopen the output > descriptor. This means you end up with two different file descriptors. > They can point to the same file, but they are not the same file > descriptor.
That's where you are wrong. freopen can be passed a NULL pointer instead of a filename in order to reuse the same file descriptor, but with an implementation-defined different mode. In cygwin's case, this means you can use freopen to swap a file between text and binary mode. > > They fixed it by using SET_BINARY(), but not on Cygwin, because I assume > SET_BINARY() is a Windows-thing, not Cygwin. SET_BINARY is an upstream coreutils thing designed for cygwin and other platforms that have O_BINARY in the first place (Debian doesn't). It is a macro that expands to either the non-standard setmode(), or the standardized (but implementation-dependent) freopen(). > > I can't really understand why Cygwin just doesn't force O_BINARY to be > set. File descriptors on UNIX are supposed to display raw file contents. That's exactly what that freopen is doing - it is forcing O_BINARY to be set, regardless of how stdin was inherited. - -- Don't work too hard, make some time for fun as well! Eric Blake e...@byu.net -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (Cygwin) Comment: Public key at home.comcast.net/~ericblake/eblake.gpg Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAklzrKgACgkQ84KuGfSFAYCZzACeJcwTKhDejFWZLP8LkhKRkv/4 bj0AniqGtXHep5FcUIavGtl2YOWeSRwQ =aiau -----END PGP SIGNATURE----- -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/
