将数组作为函数参数c

Question

I currently send commands over spi as follows:

I want to create a function to send any command passed to it. Can I pass a byte array as an argument to function? Like I have below.

Answer 1

Passing arrays is done using pointers in C.
Since arrays may decay to pointers through an implicit conversion from T[] to T* , we pass a pointer to the function referring to the array.

Write the function like ¹

void sendCommand(uint8_t* Cmd) {
    ...
}

and call it like

sendCommand(SyncCmd);

However , watch out: sizeof(Cmd) yields the size of the pointer, not the whole array , when used within sendCommand . Therefore, you need to pass the size explicitly. See this by Linus Torvalds to hear some harsh words on this matter.

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¹ Note that uint8_t[] , uint8_t* , uint8_t[42] , and friends are all equivalent when used as parameters. That is, these are all equivalent:

void foo1(uint8_t*);
void foo2(uint8_t[]);
void foo3(uint8_t[42]);

_{Thanks to @Olaf for your contribution here.}