ifstream：检查是否成功打开

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一位同事只是告诉我这个代码：

A colleague just told me that this code:

std::ifstream stream(filename.c_str()); if (!stream) { throw std::runtime_error(".."); }

他说 ifstream 如果打开成功则计算为0。我的代码工作，但我想找到文档，但没有看到它说如何检查打开是否成功。你能指点我吗？

would be wrong. He said ifstream evaluates to 0 if opening is successful. My code works, but I wanted to find the documentation but didn't see where it says how to check if opening was successful. Can you point me to it?

推荐答案

operator！ std :: ifstream ，因此您可以执行此操作，因此重新启动了rel =nofollow> 。

operator! is overloaded for std::ifstream, so you can do this.

在我看来，这是一个可怕的滥用操作符重载（由标准委员会）。如果你只是做 if（stream.fail（）），它会更清楚。

In my opinion, though, this is a horrible abuse of operator overloading (by the standards committee). It's much more explicit what you're checking if you just do if (stream.fail()).