Is there a good example of how toupper() works?

Karl Heuer karl at haddock.ima.isc.com
Fri Oct 19 07:49:00 AEST 1990


In article <1990Oct17.170914.683 at wpi.WPI.EDU> profesor at wpi.WPI.EDU (Matthew E Cross) writes:
>Nope, won't work - the return value of 'toupper' is undefined if the input is
>not a lowercase character.

Fixed in ANSI C.

For those who are using pre-ANSI systems where this doesn't hold, I recommend
coding in ANSI style, and writing your own ANSI-compatible headers and
libraries as needed.  This minimizes the trauma when you finally graduate to
ANSI C.  My personal ansi/ctype.h is:
	#include "/usr//include/ctype.h"
	#undef tolower
	#undef toupper
	#if defined(__STDC__)
	extern int toupper(int);
	extern int tolower(int);
	#else
	extern int toupper();
	extern int tolower();
	#endif

Karl W. Z. Heuer (karl at ima.isc.com or uunet!ima!karl), The Walking Lint



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