处理“-Wincompatible-pointer-types”警告

Question

我有以下导致 -Wincompatible-pointer-types 警告的代码：

union SensorData
{
    uint64_t raw_sensor_data;
    struct
    {
        uint16_t humidity_data;
        uint16_t temperature_data;
    };
} sensor_data;

/* ... Bunch of other code ...*/

uint8_t *raw_sensor_data_bytes = &sensor_data.raw_sensor_data;
uint8_t checksum = raw_sensor_data_bytes[0];
uint8_t sum = 0;
for (uint8_t i = 1; i < 8; i++)
{
    sum += raw_sensor_data_bytes[i];
}

这是导致的错误：

warning: initialization of 'uint8_t *' {aka 'unsigned char *'} from incompatible pointer type 'uint64_t *' {aka 'long long unsigned int *'} [-Wincompatible-pointer-types]
   88 |     uint8_t *raw_sensor_data_bytes = &sensor_data.raw_sensor_data;
      |                                      ^

我想我明白为什么会触发错误：这是因为我有一个指针，它期望指向一个 8 位整数，而实际上它指向一个 64 位整数；但是，这是（我目前认为的）一个很好的理由。我需要将该 64 位整数分成 8 位段，因此我认为创建一个指针会很好，实际上将 64 位整数分成 8 个 8 位段；但是，这样做会导致上述警告。有没有更合适的方法来做我想做的事情来消除警告，或者我是否可以简单地以某种方式覆盖警告，或者我只需要忽略它？

Answer 1

将对象指针转换为指向char或unsigned char（或等效）的指针以访问对象的各个字节是well-defined，只要转换通过显式转换发生：

uint8_t *raw_sensor_data_bytes = (uint8_t *)&sensor_data.raw_sensor_data;

处理“-Wincompatible-pointer-types”警告

Dealing with an `-Wincompatible-pointer-types` warning

c

warnings

compiler-warnings