php man page for iswupper

ISWUPPER(3)						     Linux Programmer's Manual						       ISWUPPER(3)

NAME
       iswupper - test for uppercase wide character

SYNOPSIS
       #include <wctype.h>

       int iswupper(wint_t wc);

DESCRIPTION
       The  iswupper() function is the wide-character equivalent of the isupper(3) function.  It tests whether wc is a wide character belonging to
       the wide-character class "upper".

       The wide-character class "upper" is a subclass of the wide-character class "alpha", and therefore also a  subclass  of  the  wide-character
       class "alnum", of the wide-character class "graph" and of the wide-character class "print".

       Being a subclass of the wide-character class "print", the wide-character class "upper" is disjoint from the wide-character class "cntrl".

       Being  a  subclass  of the wide-character class "graph", the wide-character class "upper" is disjoint from the wide-character class "space"
       and its subclass "blank".

       Being a subclass of the wide-character class "alnum", the wide-character class "upper" is disjoint from the wide-character class "punct".

       Being a subclass of the wide-character class "alpha", the wide-character class "upper" is disjoint from the wide-character class "digit".

       The wide-character class "upper" contains at least those characters wc which are equal to towupper(wc) and different from towlower(wc).

       The wide-character class "upper" always contains at least the letters 'A' to 'Z'.

RETURN VALUE
       The iswupper() function returns nonzero if wc is a wide character belonging to the wide-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 | MT-Safe locale |
       +-----------+---------------+----------------+
CONFORMING TO
       POSIX.1-2001, POSIX.1-2008, 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.

SEE ALSO
       isupper(3), iswctype(3), towupper(3)

COLOPHON
       This page is part of release 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

GNU
								    2015-08-08							       ISWUPPER(3)