C ++语言标准中是否定义了sizeof(bool)? [英] Is sizeof(bool) defined in the C++ language standard?

问题描述

我在标准文档中找不到答案. C ++语言标准是否要求sizeof(bool)始终为1(1字节)，或者此大小是实现定义的?

I can't find an answer in the standard documentation. Does the C++ language standard require sizeof(bool) to always be 1 (for 1 byte), or is this size implementation-defined?

推荐答案

sizeof(bool)是实现定义的，该标准特别强调了这一事实.

sizeof(bool) is implementation defined, and the standard puts notable emphasis on this fact.

§5.3.3/1，摘要:

§5.3.3/1, abridged:

sizeof(char)，sizeof(signed char)和sizeof(unsigned char)为1; sizeof应用于任何其他基本类型的结果是实现定义的. [注意:尤其是sizeof(bool)和sizeof(wchar_t)是实现定义的. ⁶⁹⁾]

sizeof(char), sizeof(signed char) and sizeof(unsigned char) are 1; the result of sizeof applied to any other fundamental type is implementation-defined. [Note: in particular, sizeof(bool) and sizeof(wchar_t) are implementation-defined.⁶⁹⁾]

脚注69):

sizeof(bool)不必为1.

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