ios - 无法推断通用参数 'self'

Question

我正在尝试从我正在使用的蓝牙设备转换值中的字节，但我得到 Generic parameter 'Self' could not be inferred 对此我不知道什么意思

var speed: UInt16 = 0
_ = withUnsafeBytes(of: &speed, {characteristic.value!.copyBytes(to: $0, from: 0...1)})

Answer 1

错误信息具有误导性。实际问题是 withUnsafeBytes 使用指向给定参数的原始字节的只读 缓冲区指针调用闭包。你需要的是withUnsafeMutableBytes:

var speed: UInt16 = 0
_ = withUnsafeMutableBytes(of: &speed, {
    characteristic.value!.copyBytes(to: $0, from: 0...1)
})