In the following accepted answer you can find the ingredients of the Indian curry powder.  I usually cook with Indian curry powder, however, I recently received some Sri Lankan curry powder.  The aroma is different when I use Sri Lankan curry powder, (in my opinion, better,) and it tastes different too.  Does anyone know the spices used in making Sri Lankan curry powder? 
Most of the recipes I've made for Sri Lankan curries typically have pandan, dry curry leaves, fennel, green cardamom, mustard seeds, cloves, cumin, coriander & black peppercorns. 