Style (was: C-DATABASE B-PLUS a quick look)

[Bruce Becker]

In article <2537 at xyzzy.UUCP> throopw at xyzzy.UUCP (Wayne A. Throop) writes:
>[...]
>    for( p = s; *p ++p )
>        if( *p >= 0 )
>            *p = toupper( *p );
>
>because all functions defined in ctype.h take arguments that
>are integers, but give defined results only if those integers have
>values representable as unsigned integer (or are the constant EOF).
>
>Thus, the test for negative values is (I *think*) necessary.  Unless,
>of course, you are willing to otherwise ensure that s only points at
>strings of vanilla characters... then the loop is OK as it was.


	I'd like to point out a (possibly icky) variant -


		for( p = s; *p ++p )
			*p = toupper( *p&0xff );


	This gets at possible 256-character sets in the
	environments where the compiler &/| hardware has
	sign-extended the negative byte value.
	Not all _ctype arrays have the same range - some
	are only 128 bytes. In those cases the '0xff' above
	becomes '0x7f'.
	It might be useful to add that testing for EOF is
	possible - this raises the question of its value.
	Ought it to be -1, or 0xFF, or what? I'm confused
	about what the value of "toupper(EOF)" should be...


>Wayne Throop      <the-known-world>!mcnc!rti!xyzzy!throopw

Cheers,
-- 
   _  _/\	Bruce Becker	Toronto, Ont.
   \`o O|	Internet: bdb at becker.UUCP, bruce at gpu.utcs.toronto.edu
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