The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.

#### NAME

> towlower - transliterate uppercase wide-character code to lowercase

#### SYNOPSIS

> ``#include <wctype.h>
> wint_t towlower(wint_t` wc`);
> ``

#### DESCRIPTION

> [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 IEEE Std 1003.1-2001 defers to the ISO C standard.

> The towlower() function has 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 current locale or the value of WEOF. If the argument has any other value, the behavior is undefined. If the argument of towlower() represents an uppercase wide-character code, and there exists a corresponding lowercase wide-character code (as defined by character type information in the program locale category LC_CTYPE ), the result shall be the corresponding lowercase wide-character code. All other arguments in the domain are returned unchanged.

#### RETURN VALUE

> Upon successful completion, towlower() shall return the lowercase letter corresponding to the argument passed; otherwise, it 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(), the Base Definitions volume of IEEE Std 1003.1-2001, Chapter 7, Locale, <wctype.h>, <wchar.h>

#### CHANGE HISTORY

> First released in Issue 4.

#### Issue 5

> The following change has been made in this issue for alignment with ISO/IEC 9899:1990/Amendment 1:1995 (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 DESCRIPTION is updated to avoid use of the term "must" for application requirements.

End of informative text.

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