NAME

std::towupper - std::towupper

Synopsis

Defined in header <cwctype>
std::wint_t towupper( std::wint_t ch );

Converts the given wide character to uppercase, 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

Uppercase version of ch or unmodified ch if no uppercase version is listed in the
current C locale.

Notes

Only 1:1 character mapping can be performed by this function, e.g. the uppercase
form of 'ß' is (with some exceptions) the two-character string "SS", which cannot
be obtained by std::towupper.

ISO 30112 specifies which pairs of Unicode characters are included in this mapping.

Example

The latin letter 'ſ' (U+017F) is the alternative lowercase form of 'S' (U+0053)

// Run this code

#include <iostream>
#include <cwctype>
#include <clocale>

int main()
{
wchar_t c = L'\u017f'; // Latin small letter Long S ('ſ')

std::cout << std::hex << std::showbase;
std::cout << "in the default locale, towupper(" << (std::wint_t)c << ") = "
<< std::towupper(c) << '\n';
std::setlocale(LC_ALL, "en_US.utf8");
std::cout << "in Unicode locale, towupper(" << (std::wint_t)c << ") = "
<< std::towupper(c) << '\n';
}

Output:

in the default locale, towupper(0x17f) = 0x17f
in Unicode locale, towupper(0x17f) = 0x53