c - 是否允许在位字段中使用short或任何其他类型代替int

Question

在大多数示例中我都看到过有关位字段的内容 使用unsigned int。

struct example
{
    unsigned int number: 1
}

为什么我们不能使用unsigned Short或其他一些数据类型来代替？

Answer 1

来自cppreference.com :

Bit fields can have only one of four types (possibly const or volatile qualified):

• unsigned int, for unsigned bit fields (unsigned int b:3; has the range 0..7)
• signed int, for signed bit fields (signed int b:3; has the range -4..3)
• int, for bit fields with implementation-defined signedness (Note that this differs from the meaning of the keyword int everywhere else, where it means "signed int"). For example, int b:3; may have the range of values 0..7 or -4..3.
• _Bool, for single-bit bit fields (bool x:1; has the range 0..1 and implicit conversions to and from it follow the boolean conversion rules.

Additional implementation-defined types may be acceptable.

以类似于(位域之外)unsigned char、signed char 和 char 的方式来思考这一点会有所帮助>(后者的签名是由实现定义的)。