Difference between revisions of "cpp/string/multibyte/btowc"
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Andreas Krug (Talk | contribs) m ({{c}}, headers sorted) |
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}} | }} | ||
| − | Widens a single-byte character {{ | + | Widens a single-byte character {{c|c}} 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 to {{c|wchar_t}}. | 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 to {{c|wchar_t}}. | ||
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===Return value=== | ===Return value=== | ||
| − | {{lc|WEOF}} if {{ | + | {{lc|WEOF}} if {{c|c}} is {{lc|EOF}}. |
| − | Wide character representation of {{ | + | Wide character representation of {{c|c}} if {{c|(unsigned char)c}} is a valid single-byte character in the initial shift state, {{lc|WEOF}} otherwise. |
===Example=== | ===Example=== | ||
{{example | {{example | ||
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|code= | |code= | ||
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#include <clocale> | #include <clocale> | ||
| + | #include <cwchar> | ||
| + | #include <iostream> | ||
void try_widen(char c) | void try_widen(char c) | ||
Latest revision as of 01:06, 9 June 2023
| Defined in header <cwchar>
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| std::wint_t btowc( int c ); |
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Widens a single-byte character c 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 to wchar_t.
Contents |
[edit] Parameters
| c | - | single-byte character to widen |
[edit] 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.
[edit] Example
Run this code
#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 " << +(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 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 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
[edit] See also
| narrows a wide character to a single-byte narrow character, if possible (function) | |
| [virtual] |
converts a character or characters from char to CharT (virtual protected member function of std::ctype<CharT>)
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| C documentation for btowc
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