TOWLOWER(3) Linux Programmer's Manual TOWLOWER(3)NAME
towlower, towlower_l - convert a wide character to lowercase
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)):
Since glibc 2.10:
_XOPEN_SOURCE >= 700
Before glibc 2.10:
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
The towupper_l() function performs the same task, but performs the con‐
version based on the character type information in the locale specified
by locale. The behavior of towupper_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 char‐
acter in the locale or be the value WEOF.
If wc was convertible to lowercase, towlower() returns its lowercase
equivalent; otherwise it returns wc.
Multithreading (see pthreads(7))
The towlower() function is thread-safe with exceptions. It can be
safely used in multithreaded applications, as long as setlocale(3) is
not called to change the locale during its execution.
The towlower_l() function first appeared in glibc 2.3.
CONFORMING TOtowlower(): C99, POSIX.1-2001 (XSI); present as an XSI extension in
POSIX.1-2008, but marked obsolete.
The behavior of these functions depends on the LC_CTYPE category of the
These functions are not very appropriate for dealing with Unicode char‐
acters, because Unicode knows about three cases: upper, lower and title
SEE ALSOiswlower(3), towctrans(3), towupper(3), locale(7)COLOPHON
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GNU 2014-03-18 TOWLOWER(3)