Simplest way to fill an array in a struct after declaration in one operation [duplicate]

Question

I have a structure which contain a long array. I know that possible initialize an array when defined:

uint8_t array[] = {0x10, 0x11, 0xa2, 0xa5};

My question is: is it possible to set all elements of an array after declaration in one operation? Actually, this is a variable of a stucture.

struct example
{
    uint8_t long_array[256];
};

And after creating an instance I want to set all elements for long_array to different values in one operation. If it is not possible, what is the simplest way to set all elements?

There is a pseudocode what I want to do:

struct example ex;
ex.long_array[] = {0x01, 0x07, 0x9a, 0xd1, <...>};

Thanks for your help!

Answer 1

struct Mystruct {
  int a[5];
};

int main() {

  struct Mystruct foo = {
        { 1, 2, 3, 4 }
  };
  return 0;
}

And you can have more arrays of course.

[EDIT]

About memcpy, that is mentioned in the comments, of course it is a working solution, but, you need to have the values in another array, so that you will actually copy this array to the one inside the struct.