do_unshift
STD：：codecvt：：unShift，do[医]不移位
| Defined in header | | |
|---|---|---|
| public: result unshift( StateT& state, ExternT* to, ExternT* to_end, ExternT*& to_next) const; | (1) | |
| protected: virtual result do_unshift( StateT& state, ExternT* to, ExternT* to_end, ExternT*& to_next) const; | (2) | |
1%29公共成员函数，调用成员函数。do_unshift最派生的类。
2%29如果由以下代码表示的编码codecvtfacet是状态依赖的，并且state表示不是初始Shift状态的转换状态，写入返回到初始Shift状态所需的字符。将字符写入字符数组，该数组的第一个元素由to.不超过to_end-to文字都是写的。参数to_next更新为指向最后写的字符之一。
返回值
类型值std::codecvt_base::result，说明成功情况如下：
| ok | all necessary characters were written. state now represents initial shift state |
|---|---|
| partial | not enough space in the output buffer. to_next == to_end |
| error | unspecified error occurred |
| noconv | the encoding is not state-dependent, no termination sequence necessary |
非转换专业化std::codecvt<char, char,std::mbstate_t>总是回来std::codecvt_base::noconv...
注记
此函数由std::basic_filebuf::close()在其他情况下，当最后确定状态相关的多字节字符序列时。
例
另见
| wcrtomb | converts a wide character to its multibyte representation, given state (function) |
|---|---|
| do_out virtual | converts a string from internT to externT, such as when writing to file (virtual protected member function) |
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