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[Bug regex/1278] regex undefined behavior with shifting past word length


------- Additional Comments From paolo dot bonzini at lu dot unisi dot ch  2005-09-02 06:17 -------
Subject: Re:  regex undefined behavior with shifting past
 word length


>For example, on a one's complement host, ~0 has the numeric value
>zero, i.e., ~0 == 0.  Also, ~0 is of type int.  When ~0 is converted
>to unsigned int, it is converted by value, not by bit-pattern.  (The C
>Standard requires this.)  Hence ((unsigned) ~0) is equivalent to
>((unsigned) 0), which in turn is equivalent to 0u, which is zero.
>  
>
So you want ~0u, but not -1.

Paolo


-- 


http://sources.redhat.com/bugzilla/show_bug.cgi?id=1278

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