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Date:	Fri, 24 Dec 2004 14:00:53 -0500
From:	Joe Wright <joewwright AT comcast DOT net>
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Subject:	Re: CTYPE stuff for Eli or DJ
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DJ Delorie wrote:
>>'Splain me Batman. In ctypes.ha we have the macro..
>>
>>    #define isspace(c) (__dj_ctype_flags[(int)(c)+1] & __dj_ISSPACE)
>>
>>__dj_ctype_flags is an array 257 of unsigned short.
>>
>>What assumptions are you making about '(int)(c)+1' that might ensure 
>>the required index range of 0..256 ?
> 
> 
> The ANSI C specification requires that applications pass only unsigned
> chars, or the value EOF, to the ctype functions.  Values that meet
> those requirements will not exceed the ctype array boundary.  Values
> outside those requirements indicate that your application is faulty.

Even faulty, if '(int)(c)+1' is not in range do we risk segfault or 
other awful outcome? Kaz' demons come to mind.
-- 
Joe Wright                            mailto:joewwright AT comcast DOT net
"Everything should be made as simple as possible, but not simpler."
                     --- Albert Einstein ---

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