在C中对宏参数进行类型检查 [英] Typechecking macro arguments in C

问题描述

是否可以对#define宏进行类型检查?例如:

Is it possible to typecheck arguments to a #define macro? For example:

typedef enum
{
    REG16_A,
    REG16_B,
    REG16_C
}REG16;

#define read_16(reg16)  read_register_16u(reg16); \
                        assert(typeof(reg16)==typeof(REG16));

上面的代码似乎无效.我在做什么错了?

The above code doesn't seem to work. What am I doing wrong?

顺便说一句，我正在使用gcc，并且我可以保证在此项目中将一直使用gcc.该代码不必具有可移植性.

BTW, I am using gcc, and I can guarantee that I will always be using gcc in this project. The code does not need to be portable.

推荐答案

gcc支持typeof

gcc supports typeof

例如来自Linux内核的typesafe min宏

e.g. a typesafe min macro taken from the linux kernel

#define min(x,y) ({ \
    typeof(x) _x = (x); \
    typeof(y) _y = (y); \
    (void) (&_x == &_y);        \
    _x < _y ? _x : _y; })

但是它不允许您比较两种类型.请注意，尽管指针比较会产生警告-您可以像这样进行类型检查(也可以从linux内核中进行)

but it doesn't allow you to compare two types. Note though the pointer comparison which Will generate a warning - you can do a typecheck like this (also from the linux kernel)

#define typecheck(type,x) \
({  type __dummy; \
    typeof(x) __dummy2; \
    (void)(&__dummy == &__dummy2); \
    1; \
})

大概您可以做类似的事情-即比较指向参数的指针.

Presumably you could do something similar - i.e. compare pointers to the arguments.

这篇关于在C中对宏参数进行类型检查的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！