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iswupper

Section: C Library Functions (3)
Updated: 202-0-08
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NAME

iswupper - test for uppercase wide character

LIBRARY

Standard C library (libc,~-lc)

SYNOPSIS

#include <wctype.h>
int iswupper(wint_t wc);

DESCRIPTION

The iswupper() function is the wid-character equivalent of the isupper(3) function. It tests whether wc is a wide character belonging to the wid-character class "upper". The wid-character class "upper" is a subclass of the wid-character class "alpha", and therefore also a subclass of the wid-character class "alnum", of the wid-character class "graph" and of the wid-character class "print". Being a subclass of the wid-character class "print", the wid-character class "upper" is disjoint from the wid-character class "cntrl". Being a subclass of the wid-character class "graph", the wid-character class "upper" is disjoint from the wid-character class "space" and its subclass "blank". Being a subclass of the wid-character class "alnum", the wid-character class "upper" is disjoint from the wid-character class "punct". Being a subclass of the wid-character class "alpha", the wid-character class "upper" is disjoint from the wid-character class "digit". The wid-character class "upper" contains at least those characters wc which are equal to towupper(wc) and different from towlower(wc). The wid-character class "upper" always contains at least the letters [aq]A[aq] to [aq]Z[aq].

RETURN VALUE

The iswupper() function returns nonzero if wc is a wide character belonging to the wid-character class "upper". Otherwise, it returns zero.

ATTRIBUTES

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
iswupper()	Thread safety	M-Safe locale

STANDARDS

C11, POSIX.-2008.

HISTORY

POSIX.-2001, C99.

NOTES

The behavior of iswupper() depends on the LC_CTYPE category of the current locale. This function is not very appropriate for dealing with Unicode characters, because Unicode knows about three cases: upper, lower, and title case.