| Localization library | |||||||||||||||||||||||||
| Regular expressions library(C++11) | |||||||||||||||||||||||||
| Formatting library(C++20) | |||||||||||||||||||||||||
| Null-terminated sequence utilities | |||||||||||||||||||||||||
| Byte strings | |||||||||||||||||||||||||
| Multibyte strings | |||||||||||||||||||||||||
| Wide strings | |||||||||||||||||||||||||
| Primitive numeric conversions | |||||||||||||||||||||||||
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| Text encoding identifications | |||||||||||||||||||||||||
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Defined in header <cwchar> | ||
std::wint_t btowc(int c); | ||
Widens a single-byte characterc to its wide character equivalent.
Most multibyte character encodings use single-byte codes to represent the characters from the ASCII character set. This function may be used to convert such characters towchar_t.
Contents |
| c | - | single-byte character to widen |
WEOF ifc isEOF.
Wide character representation ofc if(unsignedchar)c is a valid single-byte character in the initial shift state,WEOF otherwise.
#include <clocale>#include <cwchar>#include <iostream> void try_widen(char c){std::wint_t w= std::btowc(c);if(w!= WEOF)std::cout<<"The single-byte character "<<+(unsignedchar)c<<" widens to "<<+w<<'\n';elsestd::cout<<"The single-byte character "<<+(unsignedchar)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 ß (U+00df) in ISO-8859-4 try_widen('\xf9');// Lithuanian letter ų (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');}
Possible output:
In Lithuanian ISO-8859-4 locale:The single-byte character 0x41 widens to 0x41The single-byte character 0xdf widens to 0xdfThe single-byte character 0xf9 widens to 0x173In Lithuanian UTF-8 locale:The single-byte character 0x41 widens to 0x41The single-byte character 0xdf failed to widenThe single-byte character 0xf9 failed to widen
| narrows a wide character to a single-byte narrow character, if possible (function)[edit] | |
[virtual] | converts a character or characters fromchar toCharT(virtual protected member function of std::ctype<CharT>)[edit] |
C documentation forbtowc | |
