工具和人类很容易区分事物。就是这样。

在常规使用中(通过boost等)，.hpp是特别的c++头文件。另一方面，.h用于非c++专用的头文件(主要是C)。由于存在许多非平凡的情况，因此精确检测内容的语言通常很难，因此这种差异通常使现成的工具易于编写。对于人类来说，一旦习惯了，也就容易记忆和使用了。

然而，我要指出，公约本身并不总是如预期的那样有效。

它不受语言规范的强迫，无论是C还是c++。有许多项目不遵循惯例。一旦你需要合并(混合)它们，就会很麻烦。 .hpp本身不是唯一的选择。为什么不是。hh或。hxx?(尽管无论如何，您通常至少需要一个关于文件名和路径的常规规则。)

我个人在我的c++项目中使用。h和。hpp。我没有遵循上面的惯例，因为:

The languages used by each part of the projects are explicitly documented. No chance to mix C and C++ in same module (directory). Every 3rdparty library is required to conforming to this rule. The conformed language specifications and allowed language dialects used by the projects are also documented. (In fact, I even document the source of the standard features and bug fix (on the language standard) being used.) This is somewhat more important than distinguishing the used languages since it is too error-prone and the cost of test (e.g. compiler compatibility) may be significant (complicated and time-consuming), especially in a project which is already in almost pure C++. Filenames are too weak to handle this. Even for the same C++ dialect, there may be more important properties suitable to the difference. For example, see the convention below. Filenames are essentially pieces of fragile metadata. The violation of convention is not so easy to detect. To be stable dealing the content, a tool should eventually not only depend on names. The difference between extensions is only a hint. Tools using it should also not be expected behave same all the time, e.g. language-detecting of .h files on github.com. (There may be something in comments like shebang for these source files to be better metadata, but it is even not conventional like filenames, so also not reliable in general.)

我通常在c++的头文件中使用.hpp，并且头文件应该只以头文件的方式使用(维护)，例如作为模板库。对于.h中的其他头文件，要么有相应的.cpp文件作为实现，要么是非c++头文件。后者对于人工(或具有显式嵌入元数据的工具，如果需要的话)通过头的内容进行区分是微不足道的。

源文件的扩展名可能对您的构建系统有意义，例如，您可能在makefile中有一个用于.cpp或. C文件的规则，或者您的编译器(例如Microsoft cl.exe)可能根据扩展名将文件编译为C或c++。

因为您必须向#include指令提供整个文件名，所以头文件扩展名是不相关的。如果您愿意，您可以在另一个源文件中包含.c文件，因为它只是一个文本包含。你的编译器可能有一个选项来转储预处理输出，这将使这一点明确(微软:/P预处理到文件，/E预处理到stdout， /EP省略#line指令，/C保留注释)

你可以选择对那些只与c++环境相关的文件使用.hpp，也就是说，它们使用的特性不能用C编译。

c++ ("C Plus Plus")作为.cpp是有意义的

扩展名为.hpp的头文件没有相同的逻辑流。

There is no advantage to any particular extension, other than that one may have a different meaning to you, the compiler, and/or your tools. header.h is a valid header. header.hpp is a valid header. header.hh is a valid header. header.hx is a valid header. h.header is a valid header. this.is.not.a.valid.header is a valid header in denial. ihjkflajfajfklaf is a valid header. As long as the name can be parsed properly by the compiler, and the file system supports it, it's a valid header, and the only advantage to its extension is what one reads into it.

话虽如此，能够基于扩展准确地做出假设是非常有用的，因此对于头文件使用一组易于理解的规则将是明智的。就我个人而言，我更喜欢这样做:

If there are already any established guidelines, follow them to prevent confusion. If all source files in the project are for the same language, use .h. There's no ambiguity. If some headers are compatible with multiple languages, while others are only compatible with a single language, extensions are based on the most restrictive language that a header is compatible with. A header compatible with C, or with both C & C++, gets .h, while a header compatible with C++ but not C gets .hpp or .hh or something of the sort.

This, of course, is but one of many ways to handle extensions, and you can't necessarily trust your first impression even if things seem straightforward. For example, I've seen mention of using .h for normal headers, and .tpp for headers that only contain definitions for templated class member functions, with .h files that define templated classes including the .tpp files that define their member functions (instead of the .h header directly containing both the function declaration and the definition). For another example, a good many people always reflect the header's language in its extension, even when there's no chance of ambiguity; to them, .h is always a C header and .hpp (or .hh, or .hxx, etc.) is always a C++ header. And yet again, some people use .h for "header associated with a source file" and .hpp for "header with all functions defined inline".

考虑到这一点，主要的优势在于始终以相同的风格命名你的头文件，并使这种风格对任何检查你的代码的人来说都很明显。这样，任何熟悉您通常的编码风格的人都可以粗略地看一下，就可以确定您对任何给定扩展的意思。

我一直认为.hpp头文件是.h和.cpp文件的混合…还包含实现细节的标头。

通常，当我看到(并使用).hpp作为扩展名时，没有相应的.cpp文件。正如其他人所说，这不是一个严格的规则，只是我倾向于使用.hpp文件。

在Bjarne Stroustrup的《c++程序设计语言第三版》(第nº1本c++必读书籍)中，他使用了*.h。所以我认为最好的做法是使用*.h。

但是，*.hpp也很好!