c++ - 为什么类型关键字以 "_t"后缀结尾？

Question

我知道 size_t 有 _t 后缀，因为它的别名/typedef。但是我不明白为什么 char16_t, char32_t 和 wchar_t 包含 _t 后缀。

Answer 1

对于 wchar_t :

In C++, wchar_t is a distinct fundamental type (and thus it is not defined in <cwchar> nor any other header).

In C, this is a typedef of an integral type.

对于 char16_t和 char32_t , 在 <cuchar> / uchar.c 中定义:

In C, this header defines two macros: char16_t and char32_t, which map to unsigned integral types of the appropriate size (the same as uint_least16_t and uint_least32_t, respectively).

In C++, char16_t and char32_t are fundamental types (and thus this header does not define such macros in C++).

因此，在这两种情况下，即使它们是 C++ 中的基本类型，它们仍保留 _t为了与 C 兼容，它们是 typedef 或宏。