“结束”有什么用？这些日子？
几天前我遇到了一个微妙的错误，代码看起来像这样：
ostringstream ss;
int anInt( 7 );
ss << anInt << "HABITS";
ss << ends;
string theWholeLot = ss.str();
问题是 ends 将 '\0' 粘贴到 ostringstream 中，所以theWholeLot 实际上看起来像 "7HABITS\0" （即末尾为空）
现在这还没有出现，因为 theWholeLot 当时正在用于使用 string::c_str() 获取 const char * 部分，这意味着 null 被屏蔽，因为它只是一个分隔符。然而，当整个过程改为使用字符串时，null 突然意味着某些内容，并且诸如： 之类的比较
if ( theWholeLot == "7HABITS" )
将失败。这让我开始思考：大概 ends 的原因是对 ostrstream 时代的回溯，当时流通常不会以 null 终止，并且必须这样 >str()（然后抛出的不是 string 而是 char *）将正常工作。
然而，现在不可能从 ostringstream 中转换出 char *，使用 ends 不仅是多余的，而且有潜在的危险，我正在考虑将它们全部从我的客户代码中删除。
任何人都可以看到在仅 std::string 环境中使用 ends 的明显原因吗？
I came across a subtle bug a couple of days ago where the code looked something like this:
ostringstream ss;
int anInt( 7 );
ss << anInt << "HABITS";
ss << ends;
string theWholeLot = ss.str();
The problem was that the ends was sticking a '\0' into the ostringstream so theWholeLot actually looked like "7HABITS\0" (i.e. a null at the end)
Now this hadn't shown up because theWholeLot was then being used to take the const char * portion using string::c_str() That meant that the null was masked as it became just a delimiter. However, when this changed to use strings throughout, the null suddenly meant something and comparisons such as:
if ( theWholeLot == "7HABITS" )
would fail. This got me thinking: Presumably the reason for ends is a throwback to the days of ostrstream when the stream was not normally terminated with a null and had to be so that str() (which then cast out not a string but a char *) would work correctly.
However, now that it's not possible to cast out a char * from a ostringstream, using ends is not only superfluous, but potentially dangerous and I'm considering removing them all from my clients code.
Can anyone see an obvious reason to use ends in a std::string only environment?
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您基本上已经回答了您自己的问题，并提供了所需的详细信息。当
std::string和std::stringstream处理所有这些时，我当然想不出任何理由使用std::ends你。因此，要明确回答您的问题，不，没有理由在仅
std::string环境中使用std::ends。You've essentially answered your own question is as much detail that's needed. I certainly can't think of any reason to use
std::endswhenstd::stringandstd::stringstreamhandle all that for you.So, to answer your question explicitly, no, there is no reason to use
std::endsin astd::stringonly environment.有些 API 需要一个包含多个以零结尾的字符串的“字符串数组”，用双零来标记结尾。 Raymond Chang 最近发表了有关此内容的博客，最重要的是来证明这一点被搞砸的频率。
There are some APIs that expect a "string array" with multiple zero terminated strings, a double zero to mark the end. Raymond Chang just recently blogged about it, most of all to demonstrate how often that this gets fumbled.