c - memcpy vs 用于读取 BLE 传感器 float 的指针转换

Question

我遇到了两种读取 BLE 传感器浮点值的解决方案。 memcpy 方法简单明了，但我遇到的另一种方法对我来说不是很清楚。有人可以准确说明指针转换方法的工作原理吗？

    // Represents data read from BLE device. Float value of 1.5
    uint32_t data = 0x3fc00000;
    float sensorValue;

    // Memcpy method, makes sense and is straightforward
    memcpy(&sensorValue, &data, sizeof(sensorValue));

    // Works, but don't fully understand exactly how
    sensorValue = *(float *)&data;

Answer 1

&data 是一个指向 uint32_t 的指针。因此，(float *)&data 将其转换为指向 float 的指针。最后，*(float *)&data 取消引用该指针。

你可以做同样的事情:

uint32_t *ui32 = &data
float *f = (float *) ui32;
sensorValue = *f;

但是，确切的行为可能取决于平台。