Calling function with macro in C

November 28, 2022

I have function in C with 3 params. I want to call that function with pre-defined values. Is there any solution?

My idea which does not work.

#define PRE_DEFINED_MACRO   (10, 15 , true)

void myFunc(uint8_t temp, uint32_t value, bool valid)
{
  .... 
}
....
//call the function like that
myFunc(PRE_DEFINED_MACRO);

>Solution :

Your macro already includes parentheses, so when this …

myFunc(PRE_DEFINED_MACRO);

… is expanded, the result is:

myFunc((10, 15 , true));

You could do this instead:

myFunc PRE_DEFINED_MACRO;

I find that pretty confusing, however. Personally, I would prefer to remove the parentheses from the macro’s replacement text:

#define MYFUNC_ARGS  10, 15 , true

// ...

myFunc(MYFUNC_ARGS);

That makes it much clearer that the call to myFunc() is, in fact, a function call. The choice of macro name also makes the intended purpose of the macro much clearer.