Call function with pointers

[yiannakop]

Hi. Suppose I want to implement a function like this:

void function_name(int length, short *array)
{
array = (short*)malloc(sizeof(short)*length);
....
....
}

This unfortunatelly doesn't work. To work I must place the allocation line (array = (short*)malloc(sizeof(short)*length)
in my main(), just before calling the function.
Why is this happening?
Thanx