Initialiser list passed as function parameter for array

Question

How do I make this work:

void foo(uint8_t a[]) { ... }

foo({0x01, 0x02, 0x03});

It gives me an error:

error: cannot conver         


        

Answer 1

This:

void foo(uint8_t a[]) { ... }

is a function that takes a uint8_t*, not an array - arrays are decayed to pointers when used as function arguments. The issue is that an initializer list (like {0x01, 0x02, 0x03}) cannot be converted to a uint8_t*.

If what you want is to pass an arbitrary number of uint8_ts to foo, the simple solution is to use the new std::initializer_list

void foo(std::initializer_list a) { ... }

foo({0x01, 0x02, 0x03, 0x04, 0x05}); // OK - a has 5 elems in it

Or you could take a variadic pack and construct an array from it internally:

template ::value...>
              >>
void foo(Args... elems) {
    uint8_t a[] = {elems...};
    // ...
}

That has slightly different usage:

foo({0x01, 0x02, 0x03}); // error
foo(0x01, 0x02, 0x03; // OK - a has 3 elems in it