std::towlower
Defined in header <cwctype>
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std::wint_t towlower( std::wint_t ch ); |
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Converts the given wide character to lowercase, if possible.
If the value of ch
is neither representable as a wchar_t nor equal to the value of the macro WEOF, the behavior is undefined.
Parameters
ch | - | wide character to be converted |
Return value
Lowercase version of ch
or unmodified ch
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 std::towlower cannot be used to obtain the correct lowercase form in this case.
ISO 30112 specifies which pairs of Unicode characters are included in this mapping.
Example
Run this code
#include <iostream> #include <cwctype> #include <clocale> int main() { wchar_t c = L'\u0190'; // Latin capital open E ('Ɛ') std::cout << std::hex << std::showbase; std::cout << "in the default locale, towlower(" << (std::wint_t)c << ") = " << std::towlower(c) << '\n'; std::setlocale(LC_ALL, "en_US.utf8"); std::cout << "in Unicode locale, towlower(" << (std::wint_t)c << ") = " << std::towlower(c) << '\n'; }
Output:
in the default locale, towlower(0x190) = 0x190 in Unicode locale, towlower(0x190) = 0x25b
See also
converts a wide character to uppercase (function) | |
converts a character to lowercase using the ctype facet of a locale (function template) | |
converts a character to lowercase (function) |