This is covered in Intellectual Property Law Act.
see
https://www.lawnet.gov.lk/1946/12/31/intellectual-property-3/
There is no need to obtain registration for copyright in Sri Lanka though you need to obtain registration for Patent(eg New inventions - a flying car or Trade Mark- Dilma)
The moment you created and published it obtains (eg a novel, text book, study note) but it must qualify for protection under law.
Eg you cannot obtain copyright for sinhala or English alphabet, but if you created a book on sinhala alphabet such as prof JB Dissanayake and his wife had done for kids that creation will qualify.
Even computer programmes are protected under copyright in Sri Lanka and they are not registered in any place .
There are exceptions to this right it is not absolute
there is fair use -eg photocopying a page or pages in a book(not significant part of book-this is again arguable) for study- not for sale
If you created a note and published and if it is a creation of your own (not scientific or mathematical theories ) it will qualify for copyright. You can state in the work that it is protected by Copyright, but you can ascertain it only when someone violate it through a case filed in court.
This court process is very long and costly you may not do it if your work generate only small amount of money but if you do not care about cost of litigation you can obtain orders preventing other person from publishing and also distributing your work
In a classic case filed against film Dadayama by a writer who wrote a book on the actual case involving murder it took more than 20 years to obtain judgment in appeal in Court of Appeal.....
