`snprintf_s`假的安全感 [英] False sense of security with `snprintf_s`

问题描述

MSVC的安全 sprintf 函数具有知道目标缓冲区大小的模板版本。但是，这段代码在字节 ...

MSVC's "secure" sprintf funcions have a template version that 'knows' the size of the target buffer. However, this code happily paints 567890 over the stack after the end of bytes...

char bytes[5];
_snprintf_s( bytes, _TRUNCATE, "%s", "1234567890" );

任何想法我做错了什么，还是这是已知的错误？

Any idea what I do wrong, or is this a known bug?

（我在VS2005中工作 - 在2008或2010年没有测试）

(I'm working in VS2005 - didn't test in 2008 or 2010)

推荐答案

它似乎是 Visual C ++ 2005中的一个错误（我无法访问该链接; Google也有缓存）。

It does appear to be a bug in Visual C++ 2005 (I'm having trouble getting to that link; Google also has it cached).

我能够在Visual C ++ 2005中重现问题。在Visual C ++ 2008和2010中，字符串被正确截断（ bytes 包含 1234\0 ）和 -1 。

I was able to reproduce the problem in Visual C++ 2005. In Visual C++ 2008 and 2010, the string is correctly truncated (bytes contains 1234\0) and -1 is returned as expected.

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