Question

Hello I have small problem with followed C code:

 //Hardcoded commands:

 #define someCommand 0x1223;
 #(...)

 //functions definitions:
 void socketWrite(uint8_t address, const uint8_t *data, size_t length);

 //main task
 int main(){

 //I want send someCommand to socket
 socketWrite(0xff, &someCommand, 1);

 (...)
 }

this code give me of course compilation error:
error: ‘someCommand’ was not declared in this scope

but my question is about how write this correctly without creating new buffer data that can handle this command like this:

uint8_t * buff;
*buff = someCommand;
socketWrite(0xff, buff, 1);

Answer 1

someCommand is a #define. The C preprocessor generates a source text by replacing it by its value.
So your code looks like:

socketWrite( 0xff, &0x1223, 1 );

Taking address of 0x1223 isn’t possible.

int value = someCommand;
socketWrite( 0xff, &value, 1 );

may works

otherwise:

const int someCommand = 0x1223;

and later

socketWrite(0xff, &someCommand, 1);