在#define子句中，如何使预处理器替换变量名称中的参数? [英] In a #define clause, how to make the preprocessor replace a parameter inside a variable name?

问题描述

我有以下代码:

#define MY_MACRO(PARAM) int PARAM_int; double PARAM_double; [subsequent instructions]

不幸的是，它不起作用，这意味着未在变量名称内替换PARAM.这是可以解决的一些方法?

Unfortunately, it does not work, meaning that PARAM is not replaced inside the variables names. Is this solvable some way?

推荐答案

PARAM_int被认为是单个令牌，与PARAM不同.可以在与宏定义置标记:

PARAM_int is considered to be a single token, that is distinct from PARAM. You can concatenate tokens in a macro definition with ##:

#define MY_MACRO(PARAM) int PARAM ## _int; double PARAM ## _double;

现在，将扩展到任何你调用与宏，然后将所得的令牌将与和

Now, PARAM will expand to whatever you invoke the macro with, and then the resulting token will be pasted together with _int and _double.

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