iswlower(3)

iswlower3

Test for lowercase wide character

Usage

#include <wctype.h>

int iswlower(wint_t wc);

Library

Standard C library (libc, -lc)

Overview

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'.

Return value

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

Attributes

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

InterfaceAttributeValue
iswlower()Thread safetyMT-Safe locale

Notes

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.

Releases

14 releases since Debian 2.2 (Potato); the text changed 13 times.

  1. 2.2
  2. 3.0
  3. 3.1
  4. 4.0
  5. 5.0
  6. 6.0
  7. 7
  8. 8
  9. 9
  10. 10
  11. 11
  12. 12
  13. 13
  14. Arch

Standards

C11, POSIX.1-2008.

History

POSIX.1-2001, C99.

From man-pages 6.19-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.