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std::wctob

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

#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

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

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