关于std::string.length() std::string.size()

eclipse的代码提示获取到的描述：

  ///  Returns the number of characters in the string, not including any
  ///  null-termination.

意思大概是返回字符串的字符个数，不包括结束符

我的系统的ubuntu13.04,系统设置的编码如下：

LANG=zh_CN.UTF-8
LANGUAGE=zh_CN:zh:en_US:en
LC_CTYPE="zh_CN.UTF-8"
LC_NUMERIC=zh_CN.UTF-8
LC_TIME=zh_CN.UTF-8
LC_COLLATE="zh_CN.UTF-8"
LC_MONETARY=zh_CN.UTF-8
LC_MESSAGES="zh_CN.UTF-8"
LC_PAPER=zh_CN.UTF-8
LC_NAME=zh_CN.UTF-8
LC_ADDRESS=zh_CN.UTF-8
LC_TELEPHONE=zh_CN.UTF-8
LC_MEASUREMENT=zh_CN.UTF-8
LC_IDENTIFICATION=zh_CN.UTF-8
LC_ALL=

在此环境下执行下面的代码：

std::string str = "中国";

cout << str.size() << "," << str.length() << "," << strlen(str.c_str())<< endl;

结果为：

6，6，6

返回的其实是字节数