设置和清除位的宏 [英] Macros to set and clear bits

问题描述

我正在尝试编写一些简单的宏来简化设置和清除位的任务，这应该是一项简单的任务，但我似乎无法让它们正常工作.

Im trying to write a few simple macros to simplify the task of setting and clearing bits which should be a simple task however I cant seem to get them to work correctly.

#define SET_BIT(p,n) ((p) |= (1 << (n)))
#define CLR_BIT(p,n) ((p) &= (~(1) << (n)))

推荐答案

试试

#define CLR_BIT(p,n) ((p) &= ~((1) << (n)))

但是，由于一般宏邪恶的各种原因，我建议不要使用宏.使用内联函数并通过引用传递，如下所示:

However for various reasons of general macro evil I would advise not using a macro. Use an inline function and pass by reference, something like this:

static inline void set_bit(long *x, int bitNum) {
    *x |= (1L << bitNum);
}

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