Skip site navigation (1)Skip section navigation (2)

FreeBSD Manual Pages

  
 
  

home | help
std::btowc(3)		      C++ Standard Libary		 std::btowc(3)

NAME
       std::btowc - std::btowc

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

	  Widens a single-byte character c to its wide character equivalent.

	  Most	multibyte  character encodings use single-byte codes to	repre-
       sent the	characters
	  from the ASCII character set.	This function may be used  to  convert
       such characters
	  to wchar_t.

Parameters
	  c - single-byte character to widen

Return value
	  WEOF if c is EOF.

	  Wide	character  representation  of c	if (unsigned char)c is a valid
       single-byte
	  character in the initial shift state,	WEOF otherwise.

Example
       // Run this code

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

	void try_widen(char c)
	{
	    std::wint_t	w = std::btowc(c);
	    if(w != WEOF)
		std::cout << "The single-byte character	" << +(unsigned	char)c
			  << " widens to " << +w << '\n';
	    else
		std::cout << "The single-byte character	" << +(unsigned	char)c
			  << " failed to widen\n";
	}

	int main()
	{
	    std::setlocale(LC_ALL, "lt_LT.iso88594");
	    std::cout  <<  std::hex  <<	 std::showbase	 <<   "In   Lithuanian
       ISO-8859-4 locale:\n";
	    try_widen('A');
	    try_widen('\xdf'); // German letter	 (U+00df) in ISO-8859-4
	    try_widen('\xf9'); // Lithuanian letter  (U+0173) in ISO-8859-4

	    std::setlocale(LC_ALL, "lt_LT.utf8");
	    std::cout << "In Lithuanian	UTF-8 locale:\n";
	    try_widen('A');
	    try_widen('\xdf');
	    try_widen('\xf9');
	}

Output:
	In Lithuanian ISO-8859-4 locale:
	The single-byte	character 0x41 widens to 0x41
	The single-byte	character 0xdf widens to 0xdf
	The single-byte	character 0xf9 widens to 0x173
	In Lithuanian UTF-8 locale:
	The single-byte	character 0x41 widens to 0x41
	The single-byte	character 0xdf failed to widen
	The single-byte	character 0xf9 failed to widen

See also
	  wctob	     narrows  a	wide character to a single-byte	narrow charac-
       ter, if possible
		    (function)
	  do_widen  converts a character or characters from char to charT
	  [virtual] (virtual protected member function of std::ctype<CharT>)

http://cppreference.com		  2022.07.31			 std::btowc(3)

Want to link to this manual page? Use this URL:
<https://man.freebsd.org/cgi/man.cgi?query=std::btowc&sektion=3&manpath=FreeBSD+Ports+15.0>

home | help