std::btowc
定义于头文件 <cwchar>
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std::wint_t btowc( int c ); |
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加宽单字节字符 c
为其宽字符等价物。
大多数多字节字符编码用单字节码表示来自 ASCII 字符集的字符。此函数可用于转换这种字符为 wchar_t 。
参数
c | - | 要加宽的单字节字符 |
返回值
若 c
为 EOF 则为 WEOF 。
若 (unsigned char)c 在初始迁移状态为合法单字节字符,则为 c
的宽字符表示,否则为 WEOF 。
示例
运行此代码
#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'); // ISO-8859-4 中的德文字母 ß (U+00df) try_widen('\xf9'); // ISO-8859-4 中的立陶宛字母 ų (U+0173) std::setlocale(LC_ALL, "lt_LT.utf8"); std::cout << "In Lithuanian UTF-8 locale:\n"; try_widen('A'); try_widen('\xdf'); try_widen('\xf9'); }
输出:
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
参阅
若可能,则窄化宽字符为单字节窄字符 (函数) | |
[虚] |
将一或多个字符从 char 转换为 charT ( std::ctype<CharT> 的虚受保护成员函数) |