iswlower(3) Library Functions Manual iswlower(3)

iswlower - test for lowercase wide character

Standard C library (libc, -lc)

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

The iswlower() function is the wide-character equivalent of the islower(3) function. It tests whether wc is a wide character belonging to the wide-character class "lower".

The wide-character class "lower" 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 "lower" is disjoint from the wide-character class "cntrl".

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

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

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

The wide-character class "lower" always contains at least the letters 'a' to 'z'.

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

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

Interface Attribute Value
iswlower () Thread safety MT-Safe locale

C11, POSIX.1-2008.

POSIX.1-2001, C99.

The behavior of iswlower() 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.

islower(3), iswctype(3), towlower(3)

2023-10-31 Linux man-pages 6.06