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Re: where was mention of what creates NUL files?


On 09/17/2010 11:12 AM, Daniel Barclay wrote:
Does anyone recall a mention of what in CygWin (or possibly Emacs) creates
files with a simple name of "NUL"?

Windows automagically maps the file named "NUL", in any directory, to the equivalent of Unix' /dev/null. Cygwin doesn't create it, but all the same, portable programs should never name a file that case-insensitively matches 'nul', 'aux', or a host of other windows-magic names:


http://www.gnu.org/software/autoconf/manual/autoconf.html#File-System-Conventions

Meanwhile, cygwin 1.7 has added some magic to use native NT calls to work around these limitations, so that you can have a file that appears to be named "NUL" from within cygwin, but which is really exploiting some 16-bit values outside of Unicode. But various windows programs that use windows API (rather than lower-level NT API), including your file Explorer, have a hard time figuring out what cygwin did.

--
Eric Blake   eblake@redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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