NAME
towlower
towlower_l — transliterate
uppercase wide-character code to lowercase
SYNOPSIS
#include
<wctype.h>
wint_t towlower(wint_t wc); [CX] wint_t towlower_l(wint_t wc, locale_t locale);
DESCRIPTION
For towlower (): [CX]
The functionality described on this reference page is aligned with the ISO C
standard. Any conflict between the requirements described here and the ISO C
standard is unintentional. This volume of POSIX.1-2017 defers to the ISO C
standard.
The towlower ()
[CX] and towlower_l () functions have as
a domain a type
wint_t, the value
of which the application shall ensure is a character representable as a
wchar_t,
and a wide-character code corresponding to a valid character in the locale
used by the function or the value of WEOF. If the argument has any other
value, the behavior is undefined. If the argument of
towlower () [CX] or
towlower_l () represents an uppercase wide-character code,
and there exists a corresponding lowercase wide-character code as defined by
character type information in the current locale [CX] or
in the locale represented by locale, respectively
(category
LC_CTYPE),
the result shall be the corresponding lowercase wide-character code. All
other arguments in the domain are returned unchanged.
[CX] The behavior is undefined if the locale argument to towlower_l () is the special locale object LC_GLOBAL_LOCALE or is not a valid locale object handle.
RETURN VALUE
Upon successful completion, the towlower
() [CX] and towlower_l () functions
shall return the lowercase letter corresponding to the argument passed;
otherwise, they shall return the argument unchanged.
ERRORS
No errors are defined.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
XBD V1_chap07(7), <locale.h>, <wctype.h>
CHANGE HISTORY
First released in Issue 4.
Issue 5
The following change has been made in this version for alignment with ISO/IEC 9899/AMD1:1995 (“ISO C90, Amendment 1”) (E):
- The SYNOPSIS has been changed to indicate that this function and associated data types are now made visible by inclusion of the <wctype.h> header rather than <wchar.h>.
Issue 6
The normative text is updated to avoid use of the term "must" for application requirements.
Issue 7
The towlower_l () function is added from The Open Group Technical Standard, 2006, Extended API Set Part 4.
POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0678 [302], XSH/TC1-2008/0679 [283], and XSH/TC1-2008/0680 [283] are applied.
POSIX.1-2008, Technical Corrigendum 2, XSH/TC2-2008/0373 [685] is applied.