为什么我看到扔在一个C库？ [英] Why do I see THROW in a C library?

问题描述

当我这样做：
少/usr/include/stdio.h （这是只有一个C库 - 无关C ++）

When I do: less /usr/include/stdio.h (which is only a C library - nothing to do with C++)

我看 __ THROW 之后，相当多的函数声明。
另外，以上几个功能评论说，这是一个功能可能取消点，因此没有打上 __ THROW
这是怎么一回事呢？

I see __THROW after quite a few function declarations. Also, comments above a few functions say that 'This function is a possible cancellation point and therefore not marked with __THROW' What is all this for?

罚球，就是要对异常处理......但据我所知，C不会为其提供任何支持。

throw is meant to be for exception handling...but as far as I know, C doesn't provide any support for it.

请解释一下。

推荐答案

这头可能是C和C ++编译器该供应商之间共享。你是什​​么 __ THROW 定义为？

This header is likely shared between the C and C++ compiler for that vendor. Did you look what __THROW is defined as?

我怀疑一个类似于：

#ifdef __cplusplus
    #define __THROW throw()
#else
    #define __THROW
#endif

或者实际规格：

#ifdef __cplusplus
    #define __THROW(x) throw(x)
#else
    #define __THROW(x)
#endif

正如你所看到的，在C版本，它什么也不扩展。在C ++中，它确实你所期望的。这使得供应商重复使用相同的文件。

As you can see, in a C build, it expands to nothing. In C++, it does what you expect. This allows vendors to reuse the same file.

只是鸡蛋里挑骨头，这是不完全正确的：（这是唯一的C库 - 无关C ++）的

Just to nitpick, this isn't entirely true: "(which is only a C library - nothing to do with C++)"

C ++标准库，包括使用C标准库的能力。实际的标头是＆LT;＆CXXX GT; ，其中 XXX 是C头名。也就是说，包括C头＆LT;文件stdlib.h＆GT; 在C ++中，你做的＆LT; cstdlib＆GT; 。所以它确实有与C ++做。 ：）

The C++ standard library includes the ability to use the C standard library. The actual header is <cxxx> where xxx is the C header name. That is, to include the C header <stdlib.h> in C++, you do <cstdlib>. So it does have to do with C++. :)

这就是为什么你看到code你怎么做。复制两种不同语言的标题将是维护和清洁的噩梦。

This is why you see the code you do. Duplicating the header for two different languages would be a nightmare for maintenance and cleanliness.

这篇关于为什么我看到扔在一个C库？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！