windows UnicodeString 到 char* (UTF-8)
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UnicodeString to char* (UTF-8)
提问by zfedsa
I am using the ICU library in C++ on OS X. All of my strings are UnicodeStrings, but I need to use system calls like fopen, fread and so forth. These functions take const char* or char* as arguments. I have read that OS X supports UTF-8 internally, so that all I need to do is convert my UnicodeString to UTF-8, but I don't know how to do that.
我在 OS X 上使用 C++ 中的 ICU 库。我所有的字符串都是 UnicodeStrings，但我需要使用 fopen、fread 等系统调用。这些函数将 const char* 或 char* 作为参数。我已经读到 OS X 在内部支持 UTF-8，所以我需要做的就是将我的 UnicodeString 转换为 UTF-8，但我不知道该怎么做。
UnicodeString has a toUTF8() member function, but it returns a ByteSink. I've also found these examples: http://source.icu-project.org/repos/icu/icu/trunk/source/samples/ucnv/convsamp.cppand read about using a converter, but I'm still confused. Any help would be much appreciated.
UnicodeString 有一个 toUTF8() 成员函数，但它返回一个 ByteSink。我还找到了这些示例：http: //source.icu-project.org/repos/icu/icu/trunk/source/samples/ucnv/convsamp.cpp并阅读了有关使用转换器的信息，但我仍然感到困惑. 任何帮助将非常感激。
采纳答案by Steven R. Loomis
call UnicodeString::extract(...)to extract into a char*, pass NULL for the converter to get the default converter (which is in the charset which your OS will be using).
调用UnicodeString::extract(...)以提取到 char*，为转换器传递 NULL 以获得默认转换器（在您的操作系统将使用的字符集中）。
回答by Map X
ICU User Guide > UTF-8provides methods and descriptions of doing that.
ICU 用户指南 > UTF-8提供了这样做的方法和描述。
The simplest way to use UTF-8 strings in UTF-16 APIs is via the C++
icu::UnicodeStringmethodsfromUTF8(const StringPiece &utf8)andtoUTF8String(StringClass &result). There is alsotoUTF8(ByteSink &sink).
在 UTF-16 API 中使用 UTF-8 字符串的最简单方法是通过 C++
icu::UnicodeString方法fromUTF8(const StringPiece &utf8)和toUTF8String(StringClass &result). 还有toUTF8(ByteSink &sink)。
And extract()is not prefered now.
而extract()现在不优先。
Note:
icu::UnicodeStringhas constructors,setTo()andextract()methods which take either a converter object or a charset name. These can be used for UTF-8, but are not as efficient or convenient as thefromUTF8()/toUTF8()/toUTF8String()methods mentioned above.
注意：
icu::UnicodeString具有构造函数setTo()和extract()采用转换器对象或字符集名称的方法。这些可用于UTF-8，但效率不高或方便作为fromUTF8()/toUTF8()/toUTF8String()方法如上所述。
回答by gsf
This will work:
这将起作用：
std::string utf8;
uStr.toUTF8String(utf8);
