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Re: Updated: [Patch, c* ,ObjC*] handle string objects in format checking.


On Mon, 1 Nov 2010, Nicola Pero wrote:

> Probably ObjC could return the constant string converted to UTF-8 so that 
> it can be fed into c-format.c without particular any changes to c-format.c ?

What's really wanted - to do wide string format checking for wprintf etc. 
(bug 38308), not just for ObjC - are separate accessors / iterators that 
in the narrow string case extract a byte, or a multibyte character, from a 
string.  (C format strings are complicated mixtures of bytes and multibyte 
characters.)  In the wide string case both would just end up extracting a 
single wide character.  It would be strongly desirable to have a design 
for string access that is not specific to format checking but can be used 
everywhere else that looks at contents of strings.  (All such 
optimizations - folding, built-in functions, etc. - ought to work equally 
on narrow and wide strings; I don't think they do at present.)

I will no longer ask that such changes actually define the formats for 
strings for non-8-bit-bytes as I did previously, and rather too 
forcefully, in response to 
<http://gcc.gnu.org/ml/gcc-patches/2001-12/msg01579.html>.  As long as you 
set up central infrastructure for iterating over strings it will be 
significantly easier for anyone adding such a target in future to define 
things in one place and fix other places to use the common infrastructure.  
Nor will I ask that the character set issues (bugs 20110 and 33748) 
necessarily be fixed at the same time.

-- 
Joseph S. Myers
joseph@codesourcery.com


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