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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ATTRIBUTES | STANDARDS | STANDARDS | NOTES | SEE ALSO | COLOPHON |
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towlower(3) Library Functions Manual towlower(3)
towlower, towlower_l - convert a wide character to lowercase
Standard C library (libc, -lc)
#include <wctype.h>
wint_t towlower(wint_t wc);
wint_t towlower_l(wint_t wc, locale_t locale);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
towlower_l():
Since glibc 2.10:
_XOPEN_SOURCE >= 700
Before glibc 2.10:
_GNU_SOURCE
The towlower() function is the wide-character equivalent of the
tolower(3) function. If wc is an uppercase wide character, and
there exists a lowercase equivalent in the current locale, it
returns the lowercase equivalent of wc. In all other cases, wc is
returned unchanged.
The towlower_l() function performs the same task, but performs the
conversion based on the character type information in the locale
specified by locale. The behavior of towlower_l() is undefined if
locale is the special locale object LC_GLOBAL_LOCALE (see
duplocale(3)) or is not a valid locale object handle.
The argument wc must be representable as a wchar_t and be a valid
character in the locale or be the value WEOF.
If wc was convertible to lowercase, towlower() returns its
lowercase equivalent; otherwise it returns wc.
For an explanation of the terms used in this section, see
attributes(7).
┌───────────────────────────────┬───────────────┬────────────────┐
│ Interface │ Attribute │ Value │
├───────────────────────────────┼───────────────┼────────────────┤
│ towlower() │ Thread safety │ MT-Safe locale │
├───────────────────────────────┼───────────────┼────────────────┤
│ towlower_l() │ Thread safety │ MT-Safe │
└───────────────────────────────┴───────────────┴────────────────┘
towlower()
C11, POSIX.1-2008 (XSI).
towlower_l()
POSIX.1-2008.
towlower()
C99, POSIX.1-2001 (XSI). Obsolete in POSIX.1-2008 (XSI).
towlower_l()
glibc 2.3. POSIX.1-2008.
The behavior of these functions depends on the LC_CTYPE category
of the locale.
These functions are not very appropriate for dealing with Unicode
characters, because Unicode knows about three cases: upper, lower,
and title case.
iswlower(3), towctrans(3), towupper(3), locale(7)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-05-17 towlower(3)
Pages that refer to this page: iswlower(3), toupper(3), towctrans(3), towupper(3), wcscasecmp(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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