我在哪里可以找到 size_t 的定义?

2021-12-13 00:00:00 c variables c++

我看到用这种类型定义的变量,但我不知道它来自哪里,也不知道它的目的是什么.为什么不使用 int 或 unsigned int?(其他类似"类型呢?Void_t 等).

I see variables defined with this type but I don't know where it comes from, nor what is its purpose. Why not use int or unsigned int? (What about other "similar" types? Void_t, etc).

推荐答案

来自 维基百科

stdlib.hstddef.h 头文件定义了一个名为 size_t1 用于表示对象的大小.接受大小的库函数期望它们是 size_t 类型,并且 sizeof 运算符的计算结果为 size_t.

The stdlib.h and stddef.h header files define a datatype called size_t1 which is used to represent the size of an object. Library functions that take sizes expect them to be of type size_t, and the sizeof operator evaluates to size_t.

size_t 的实际类型是平台相关的;一个常见的错误是假设 size_t 与 unsigned int 相同,这会导致编程错误,2 特别是随着 64 位架构变得越来越流行.

The actual type of size_t is platform-dependent; a common mistake is to assume size_t is the same as unsigned int, which can lead to programming errors,2 particularly as 64-bit architectures become more prevalent.

来自 C99 7.17.1/2

以下类型和宏定义在标准头文件stddef.h

The following types and macros are defined in the standard header stddef.h

size_t

这是sizeof运算符结果的无符号整数类型

which is the unsigned integer type of the result of the sizeof operator

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