Code

 Header...
// myfun expects the address of a float (and implicitly that
// this float is the first elemnt of an array)
 void myfun(float p[]){
   ... 

»  p0=3.7;// Set the first element of the array
}

 int main(){
   ... 

»  float farray[12];

»  myfun(farray);

»  printf("%g\n", farray0);// Prints 3.7
»  return 0;
}