Go中的uint32和bool类型不匹配

问题描述：

I have a C macro defined like this:

#define normalize(c, a) c = (a) + ((a) == 0xFFFFFFFF)

I was rewriting it in Go, and as long as I know there is no such things as C macros in Go. Therefore, I created a normal function:

func normalize(a uint32, c *uint32) {
    *c = a + (a == 0xFFFFFFFF)
}

The problem is that this gives me a type mismatch error. Any ideas how to fix it?

我有一个如下定义的C宏： p>

 ＃ 定义normalize（c，a）c =（a）+（（a）== 0xFFFFFFFF）
  code>  pre> 
 
 我在Go中重写了它，只要 知道Go中没有C宏之类的东西。 因此，我创建了一个普通函数： p> 
 
 
  func normalize（a uint32，c * uint32）{
 * c = a +（a == 0xFFFFFFFF）
} \  n  code>  pre> 
 
 问题是，这给了我一个类型不匹配的错误。 有任何解决办法吗？ p> 
  div>

答

So your C normalize macro assigns c to a if a is not equal to 0xffffffff, or to 0 otherwise. I'm not sure what kind of normalization it is, but it's not my concern now.

So given the Go function signature you provided, this would work:

func normalize(a uint32, c *uint32) {
    if a != 0xffffffff {
        *c = a
    } else {
        *c = 0
    }
}

However, I'm not sure why not just return a value instead of writing it via c pointer?

func normalize(a uint32) {
    if a != 0xffffffff {
        return a
    }
    return 0
}

Side note: the same applies to your C macro. By the way, the macro evaluates a twice, this might come as a surprise if you ever pass some function with side effects as a. Any reason not to use (inline) function instead of a macro, or at least make it so that it evaluates to a new value, instead of assigning c to it?

Go中的uint32和bool类型不匹配

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