On 07/05/2011 09:45 AM, John Cowan wrote: > Eric Blake scripsit: > >> [B]ut if filename is _not_ a character string in the current locale, then >> the output would _not_ be a text file (among other things, a text file >> has the property that at least one locale can interpret every byte >> sequence in the file as valid characters). > > Say what? The name of a file is not a byte sequence in the file. I > don't see how it follows that because a file is a text file, its name > is a character string in some locale.
When used according to POSIX, the 'decode_pathname' argument (POSIX notation, or REMOTEFILE argument in 'uuencode --help' notation) is output literally in the resulting output of 'uuencode' on the line starting with "begin"; that resulting output is also required by POSIX to be a text file. It also helps to read elsewhere in the POSIX requirements on uuencode: "If there are characters in decode_pathname that are not in the portable filename character set the results are unspecified." Therefore, you _cannot_ use uuencode to pass the name of a file that contains non-portable characters and still have output that complies with POSIX. Which means that for our particular implementation of uuencode, if we encounter a file name that contains any bytes not already in the portable file name set, then we can do whatever we want (error out, or output some sort of prefix line that tells knowledgeable uudecode implementations that we are about to send an encoded form of a file name, output a binary file rather than a text file [by outputting the file name as a literal sequence of bytes, even though those bytes are not characters in the current locale], or anything else), all as an extension to POSIX. Of course, our goal should be to have the out-of-the-box behavior provide the most likely use (that is, it would be better if we could just make uuencode work on all possible file names, even on the ones where POSIX does not require any particular behavior). -- Eric Blake ebl...@redhat.com +1-801-349-2682 Libvirt virtualization library http://libvirt.org
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