std::towlower
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Null-terminated wide strings
(C++11)
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Defined in header
<cwctype>
std::wint_t towlower( std::wint_t ch );
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.
Contents
[edit] Parameters
ch
-
wide character to be converted
[edit] Return value
Lowercase version of ch or unmodified ch if no lowercase version is listed in the current C locale.
[edit] 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.
[edit] Example
Run this code
#include <clocale> #include <cwctype> #include <iostream> 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(" << static_cast<std::wint_t >(c) << ") = " << std::towlower(c) << '\n'; std::setlocale (LC_ALL, "en_US.utf8"); std::cout << "in Unicode locale, towlower(" << static_cast<std::wint_t >(c) << ") = " << std::towlower(c) << '\n'; }
Output:
in the default locale, towlower(0x190) = 0x190 in Unicode locale, towlower(0x190) = 0x25b
[edit] See also
C documentation for towlower