我很好奇，在 C/C++ 中，# 是什么意思？

例如，#if。它叫做“hashtag if”吗？

最佳答案

源代码中以#if 开头的行称为preprocessor directive如今。在 The C Programming Language ("K&R")¹ 一书中，它被称为“编译器控制线”。

#这个符号本身好像没有什么特别的名字。例如，documentation for the gcc compiler只是称它为“#”:

Preprocessing directives are lines in your program that start with ‘#’. Whitespace is allowed before and after the ‘#’. The ‘#’ is followed by an identifier, the directive name. It specifies the operation to perform. Directives are commonly referred to as ‘#name’ where name is the directive name. For example, ‘#define’ is the directive that defines a macro.

K&R 书中也只是称其为“#”:

Lines beginning with # communicate with this preprocessor.

¹ 丹尼斯·里奇，布赖恩·科尼汉； C 程序设计语言，第 1 版(1978 年)； p. 207

https://stackoverflow.com/questions/66548702/