towlower

Defined in header `<wctype.h>`
wint_t towlower( wint_t wc );		(since C95)

Converts the given wide character to lowercase, if possible.

Parameters

wc

-

wide character to be converted

Return value

Lowercase version of wc or unmodified wc if no lowercase version is listed in the current C locale.

Notes

Only 1:1 character mapping can be performed by this function, e.g. the Greek uppercase letter 'Σ' has two lowercase forms, depending on the position in a word: 'σ' and 'ς'. A call to towlower cannot be used to obtain the correct lowercase form in this case.

Example

Run this code

#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
#include <locale.h>
 
int main(void)
{
    wchar_t wc = L'\u0190'; // Latin capital open E ('Ɛ')
    printf("in the default locale, towlower(%#x) = %#x\n", wc, towlower(wc));
    setlocale(LC_ALL, "en_US.utf8");
    printf("in Unicode locale, towlower(%#x) = %#x\n", wc, towlower(wc));
}

Output:

in the default locale, towlower(0x190) = 0x190
in Unicode locale, towlower(0x190) = 0x25b

References

C11 standard (ISO/IEC 9899:2011):

7.30.3.1.1 The towlower function (p: 453)

C99 standard (ISO/IEC 9899:1999):

7.25.3.1.1 The towlower function (p: 399)

Language
headers
Type support
Dynamic memory management
Error handling
Program utilities
Variadic function support
Date and time utilities
Strings library
Algorithms
Numerics
Input/output support
Localization support
Thread support (C11)
Atomic operations (C11)
Technical Specifications

towupper (C95)	converts a wide character to uppercase (function)
tolower	converts a character to lowercase (function)
C++ documentation for towlower