NAME¶

std::wctob - std::wctob

Synopsis¶

Defined in header <cwchar>
int wctob( std::wint_t c );

Narrows a wide character c if its multibyte character equivalent in the initial
shift state is a single byte.

This is typically possible for the characters from the ASCII character set, since
most multibyte encodings (such as UTF-8) use single bytes to encode those
characters.

Parameters¶

c - wide character to narrow

Return value¶

EOF if c does not represent a multibyte character with length 1 in initial shift
state.

Otherwise, the single-byte representation of c as unsigned char converted to int.

Example¶

// Run this code

#include <clocale>
#include <cwchar>
#include <iostream>

void try_narrowing(wchar_t c)
{
int cn = std::wctob(c);
if (cn != EOF)
std::cout << '\'' << int(c) << "' narrowed to " << +cn << '\n';
else
std::cout << '\'' << int(c) << "' could not be narrowed\n";
}

int main()
{
std::setlocale(LC_ALL, "th_TH.utf8");
std::cout << std::hex << std::showbase << "In Thai UTF-8 locale:\n";
try_narrowing(L'a');
try_narrowing(L'๛');

std::setlocale(LC_ALL, "th_TH.tis620");
std::cout << "In Thai TIS-620 locale:\n";
try_narrowing(L'a');
try_narrowing(L'๛');
}

Output:¶

In Thai UTF-8 locale:
'0x61' narrowed to 0x61
'0xe5b' could not be narrowed
In Thai TIS-620 locale:
'0x61' narrowed to 0x61
'0xe5b' narrowed to 0xfb

See also¶

btowc widens a single-byte narrow character to wide character, if possible
(function)
narrow narrows characters
(public member function of std::basic_ios<CharT,Traits>)
narrow invokes do_narrow
(public member function of std::ctype<CharT>)
C documentation for
wctob