Help with struct variable
The typedef is no longer needed, using the 'struct' with a name declares the type.

// Arduino Uno

struct buttons
{ 
  int color[3];
  int positions[4];
  char init[20];
  void (*fn)();
};

// Declare the functions here, or use prototyping
void func1();
void func2();

buttons test[] = 
{
  { {0,0,0},    {0,0,100,100}, "getSomething",  func1 },
  { {40,40,40}, {50,50,10,10}, "somethingElse", func2 },
};

void setup()
{
  Serial.begin(9600);
  Serial.println("Calling the functions:");

  test[0].fn();
  test[1].fn();
}

void loop()
{
}

void func1()
{
  Serial.println("func1");
}

void func2()
{
  Serial.println("func2");
}