什么是一个type后跟_T（下划线-T）再present？ [英] What does a type followed by _t (underscore-t) represent?

问题描述

这似乎是一个简单的问题，但我不能与堆栈溢出的搜索或谷歌找到它。什么是一个类型后跟一个 _t 是什么意思？如

This seems like a simple question, but I can't find it with the Stack Overflow search or Google. What does a type followed by a _t mean? Such as

int_t anInt;

我看到了很多用C code旨在密切处理硬件我不禁觉得他们的关系。

I see it a lot in C code meant to deal closely with hardware—I can't help but think that they're related.

推荐答案

由于道格拉斯·梅尔指出，它基本上代表类型名称。因此，你会不明智的结束与 _t '变量或函数的名称，因为它可能会导致一些混乱。以及为size_t 中，C89标准定义 wchar_t的， off_t ， ptrdiff_t的，也许其他一些我忘了。 C99标准定义了很多额外的类型，如 uintptr_t形式，的还会将intmax_t ，中int8_t ， uint_least16_t ， uint_fast32_t ，等等。 stdint.h＆GT; 但多数情况下，你会使用＆LT; inttypes.h＆GT; ＆LT正式确定>这（异常标准C头）包括＆LT; stdint.h＆GT; 。它（＆LT; inttypes.h＆GT; ）还定义了宏与的printf（）和<$ C $使用C> scanf（）的。

As Douglas Mayle noted, it basically denotes a type name. Consequently, you would be ill-advised to end variable or function names with '_t' since it could cause some confusion. As well as size_t, the C89 standard defines wchar_t, off_t, ptrdiff_t, and probably some others I've forgotten. The C99 standard defines a lot of extra types, such as uintptr_t, intmax_t, int8_t, uint_least16_t, uint_fast32_t, and so on. These new types are formally defined in <stdint.h> but most often you will use <inttypes.h> which (unusually for standard C headers) includes <stdint.h>. It (<inttypes.h>) also defines macros for use with the printf() and scanf().

马特·柯蒂斯指出，没有在后缀编译器没有意义;它是一种以人为本的约定。

As Matt Curtis noted, there is no significance to the compiler in the suffix; it is a human-oriented convention.

不过，你也应该注意到，POSIX定义了很多的 _t 结尾的额外的类型名字，并保留实施的后缀。这意味着，如果你是在POSIX相关系统的工作，并约定定义你自己的类型名称是不明智的。我工作，对系统做了（超过20岁）;我们经常得到通过定义类型具有相同的名称，我们定义系统绊倒。

However, you should also note that POSIX defines a lot of extra type names ending in '_t', and reserves the suffix for the implementation. That means that if you are working on POSIX-related systems, defining your own type names with the convention is ill-advised. The system I work on has done it (for more than 20 years); we regularly get tripped up by systems defining types with the same name as we define.

这篇关于什么是一个type后跟_T（下划线-T）再present？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！