_toupper - transliterate lowercase characters to uppercase
[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.
islower() , toupper() , the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 7, Locale, <ctype.h>
First released in Issue 1. Derived from Issue 1 of the SVID.
The DESCRIPTION is updated to avoid use of the term "must" for application requirements.