我应该使用 C++ reinterpret_cast 优于 C 风格的强制转换？
我有以下模板函数，用于将任何标准类型的数据转储到二进制输出流中。
template<typename T> static void
dump ( const T& v, ostream& o ) {
o.write ( reinterpret_cast<const char*>(&v), sizeof(T));
}
我还可以使用 C 风格（const char*）来代替reinterpret_cast。使用reinterpret_cast 有什么特殊原因吗？我读过一些其他的文章，其中reinterpret_cast 被人皱眉。但上面的用法是合法的，不能用其他东西代替，对吗？
I have the following template function used to dump data of any standard type into a binary output stream.
template<typename T> static void
dump ( const T& v, ostream& o ) {
o.write ( reinterpret_cast<const char*>(&v), sizeof(T));
}
Instead of the reinterpret_cast I could also use a C-style (const char*). Is there any particular reason to use reinterpret_cast? I read a few other posts where reinterpret_cast was frowned upon. But the above usage is legal and cannot be replaced with anything else, right?
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（4）
C-Style 类型转换的问题在于它们在幕后做了很多工作。请参阅此处了解详细说明： http://anteru.net/2007/12/18/200 /
您应该尝试始终使用 C++ 类型转换，从长远来看，这会让生活变得更轻松。在这种情况下，C 风格转换的主要问题是，您可以编写
(char*)(&v)而使用reinterpret_cast，则需要额外的 < code>const_cast，所以更安全一些。另外，您可以使用正则表达式轻松找到reinterpret_cast，这对于 C 风格的强制转换是不可能的。The problem with C-Style casts is that they do a lot under the hood. See here for a detailed explanation: http://anteru.net/2007/12/18/200/
You should try to always use the C++-casts, makes life easier in the long run. The main problem with C-style casts in this case is that you could have written
(char*)(&v)while withreinterpret_cast, you would need an additionalconst_cast, so it's a bit safer. Plus you can easily findreinterpret_castwith a regex, which is not possible for the C-style casts.没有什么区别。在给定的情况下，C 风格的演员阵容恰恰是“重新解释”演员阵容。
您应该更喜欢 C++ 风格的强制转换的原因是它们对于所强制转换的内容是明确的。如有必要，C 风格的强制转换将始终尝试使用最原始的强制转换，而 C++ 风格的强制转换仅在可能的情况下才进行编译：静态强制转换仅在值可转换或指针/引用时才会成功是兼容的，并且只有当源和目标是彼此的 cv 限定版本时，const 转换才有效。重新解释转换明确表明您希望检查底层二进制表示形式。 （请注意，唯一有效的重新解释转换通常是那些到 void 或 char 指针，除非它们是某些更大诡计的一部分。）
There is no difference. In the given situation, the C-style cast is precisely a "reinterpret"-cast.
The reason you should prefer C++-style casts is that they are explicit about what they are casting. A C-style cast will always try to fall back on the crudest possible cast if necessary, while the C++-style cast only compiles if it is possible as intended: a static cast only succeeds if either the values are convertible or the pointers/references are compatible, and a const-cast only works if source and target are cv-qualified versions of one another. A reinterpret-cast states explicitly that you wish to examine an underlying binary representation. (Note that the only valid reinterpret-casts are usually those to void- or char-pointer, unless they're part of some larger trickery.)
C风格的铸造是非常非常危险的。因此，C++ 根据典型用法将转换分类为以下类型，
dynamic_cast(表达式) - 允许在适当的类层次结构之间进行转换。
const_cast(表达式) - 抛弃 const 性。
static_cast(表达式) - 在一定程度上是 C 风格，但仍然尊重类型之间的一些不兼容性并且不允许。
reinterpret_cast(表达式) - 如果仍然不满足要求，则可以使用此方法。 C 风格的铸造，但有名字。因此，在大型代码库中很容易找到它。
注意：- 大多数“reinterpret_cast”可以通过适当的设计来消除。换句话说，需要“reinterpret_cast”意味着设计中很可能存在错误。
更新：
这应该是最后一个选项，在上面的情况下，用法是正确的。现在提到reinterpret_cast会给读者这样的印象：作者故意选择不关心类型安全。但使用 c 风格的转换不会给人这种印象。
C style casting is very very dangerous. So C++ categorical divided the casting to below types based on typical usage,
dynamic_cast(expression) - Allows casting between proper class hierarchic.
const_cast(expression) - Casts away const-ness.
static_cast(expression) - To an extent C style but still respects some incompatibilities between types and do not allow.
reinterpret_cast(expression) - If still the requirement is not met, this is available. C style casting but with a name. So it will be easy to find it in large code base.
Note:- Most "reinterpret_cast" can be eliminated with proper design. In other words "reinterpret_cast" is needed means, most-likely something is wrong in the design.
Update:
This should be the last option, and in the case above, the usage is correct. Now mentioning reinterpret_cast will give the reader the impression that intentionally the writer have chosen not to care type safety. But using c style casting will not give that impression.
当使用
reinterpret_cast来替换static_cast或dynamic_cast时，会引起不满。鼓励使用它来替代 C 型铸件。新的演员阵容比 C 风格的演员阵容有优势。一方面，您可以限制实际想要的演员阵容，另一方面，对新演员阵容进行文本搜索比对 C 演员阵容进行文本搜索要容易得多。
reinterpret_castis frowned upon when it's used to replace astatic_castordynamic_cast. Using it to replace a C cast is encouraged.The new casts have benefits over C-style casts. For one, you can limit what cast you actually want, for another it's far easier to do a textual search for the new casts than for C casts.