C 中的 size_t 是什么? [英] What is size_t in C?

问题描述

我对 C 中的 size_t 感到困惑.我知道它是由 sizeof 运算符返回的.但究竟是什么呢?是数据类型吗?

I am getting confused with size_t in C. I know that it is returned by the sizeof operator. But what exactly is it? Is it a data type?

假设我有一个 for 循环:

Let's say I have a for loop:

for(i = 0; i < some_size; i++)

我应该使用 int i; 还是 size_t i;?

Should I use int i; or size_t i;?

推荐答案

来自维基百科:

根据 1999 ISO C 标准(C99), size_t 是一个无符号整数至少 16 位的类型(参见章节7.17 和 7.18.3).

According to the 1999 ISO C standard (C99), size_t is an unsigned integer type of at least 16 bit (see sections 7.17 and 7.18.3).

size_t 是无符号数据类型由几个 C/C++ 标准定义，例如C99 ISO/IEC 9899 标准，stddef.h 中定义的.1 它可以通过包含进一步进口stdlib.h 作为这个文件内部子包括 stddef.h.

size_tis an unsigned data type defined by several C/C++ standards, e.g. the C99 ISO/IEC 9899 standard, that is defined in stddef.h.1 It can be further imported by inclusion of stdlib.h as this file internally sub includes stddef.h.

该类型用于表示物体的大小.库函数接受或返回尺寸期望它们属于类型或具有返回类型size_t.此外，最常用的基于编译器的运算符 sizeof 应评估为兼容的常数值size_t.

This type is used to represent the size of an object. Library functions that take or return sizes expect them to be of type or have the return type of size_t. Further, the most frequently used compiler-based operator sizeof should evaluate to a constant value that is compatible with size_t.

作为暗示，size_t 是一种保证保存任何数组索引的类型.

As an implication, size_t is a type guaranteed to hold any array index.

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