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Re: Text search segmentation fault

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Tom Lane <tgl@xxxxxxxxxxxxx> writes:

> Gregory Stark <stark@xxxxxxxxxxxxxxxx> writes:
>> Maybe I'm missing something but I don't understand how this fixes the problem.
>> s is a "char*" so type punning it to an unsigned char * before dereferencing
>> it is really the same as casting it to unsigned char directly
>
> No, it isn't.  If char is signed then you'll get quite different results
> from a high-bit-set byte value, because sign extension will happen
> before the value is reinterpreted as unsigned.

What I wrote is correct. There's no sign extension if you're casting from
signed char to unsigned char since there's no extension.

I really think he should just change all the "unsigned int" into "unsigned
char" and not do the type punning with pointer casts. That's just evil.

-- 
  Gregory Stark
  EnterpriseDB          http://www.enterprisedb.com
  Ask me about EnterpriseDB's Slony Replication support!

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