The Open Group Base Specifications Issue 8
IEEE Std 1003.1-2024
Copyright © 2001-2024 The IEEE and The Open Group

NAME

towlower, towlower_l — transliterate uppercase wide-character code to lowercase

SYNOPSIS

#include <wctype.h>

wint_t towlower(wint_t
wc);

[CX] [Option Start] wint_t towlower_l(wint_t wc, locale_t locale); [Option End]

DESCRIPTION

For towlower(): [CX] [Option Start]  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.1-2024 defers to the ISO C standard. [Option End]

The towlower() [CX] [Option Start] and towlower_l() [Option End]  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] [Option Start]  or towlower_l() [Option End] 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] [Option Start]  or in the locale represented by locale, [Option End]  respectively (category LC_CTYPE ), the result shall be the corresponding lowercase wide-character code. All other arguments in the domain are returned unchanged.

[CX] [Option Start] 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. [Option End]

RETURN VALUE

Upon successful completion, the towlower() [CX] [Option Start]  and towlower_l() [Option End]  functions shall return the lowercase letter corresponding to the argument passed; otherwise, they shall return the argument unchanged.

ERRORS

No errors are defined.


The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

setlocale , uselocale

XBD 7. Locale , <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 9899:1990/Amendment 1:1995 (E):

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.

End of informative text.

 

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