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ISUPPER(3) Library Functions Manual ISUPPER(3)

isupperupper-case character test

#include <ctype.h>

isupper(int c);

The () function tests for any upper-case letter or any of an implementation-defined set of characters for which none of iscntrl(3), isdigit(3), ispunct(3), or isspace(3) is true. In the C locale, isupper() returns true only for the characters defined as upper-case letters.

The isupper() macro returns zero if the character tests false or non-zero if the character tests true.

isalnum(3), isalpha(3), isascii(3), isblank(3), iscntrl(3), isdigit(3), isgraph(3), islower(3), isprint(3), ispunct(3), isspace(3), isxdigit(3), stdio(3), toascii(3), tolower(3), toupper(3), ascii(7)

The isupper() function conforms to ANSI X3.159-1989 (“ANSI C89”).

The argument to isupper() must be EOF or representable as an unsigned char; otherwise, the result is undefined.

May 31, 2007 OpenBSD-5.1