_toupper - transliterate lowercase characters to uppercase [OB
XSI] #include <ctype.h> int _toupper(int c); The _toupper()
macro shall be equivalent to toupper() except that the
application shall ensure that the argument c is a lowercase
letter. Upon successful completion, _toupper() shall return the
uppercase letter corresponding to the argument passed. No errors
are defined. Applications should use the toupper() function
instead of the obsolescent _toupper() function. The _toupper()
function may be removed in a future version. XBD Locale,
<ctype.h> First released in Issue 1. Derived from Issue 1 of the
SVID. The normative text is updated to avoid use of the term
"must" for application requirements. The _toupper() function is
marked obsolescent. return to top of page