Messages in this thread | | | Subject | Re: [PATCH] lib/vsprintf: add %pT[C012] format specifier | From | Joe Perches <> | Date | Wed, 01 Jan 2014 17:33:09 -0800 |
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On Wed, 2014-01-01 at 19:02 +0900, Tetsuo Handa wrote: > Joe Perches wrote: > > > This choice (i.e. reserve only '\xFF') is more resource economy than my > > > previous choice (i.e. reserve '\x7F' to '\xFF') at the cost of wasting only > > > one byte compared to my previous choice. > > > > I supposed that's better. > > > > Is there a particularly utility/reason to use 0xff > > vs ascii SUB/PU1/PU2? > > > Nothing. Is 0x1A preferable to 0xFF?
ASCII SUB seems to me to fit better for the purpose. The "Private Use" PU1/PU2 also seemed appropriate, but I suppose any non-printable character might be OK.
(from wikipedia)
The substitute character (SUB) was intended to request a translation of the next character from a printable character to another value, usually by setting bit 5 to zero. This is handy because some media (such as sheets of paper produced by typewriters) can transmit only printable characters. However, on MS-DOS systems with files opened in text mode, "end of text" or "end of file" is marked by this Ctrl-Z character, instead of the Ctrl-C or Ctrl-D, which are common on other operating systems.
PU1/PU2:
Reserved for a function without standardized meaning for private use as required, subject to the prior agreement of the sender and the recipient of the data.
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