[superhuzza]

Yes, if it's a FIDE tournament, there is a precise definition about what is allowed. Of course, this will be applied as interpreted by the arbiters.

12.3 a. During play the players are forbidden to make use of any notes, sources of information or advice, or analyse on another chessboard.

12.3 b. Without the permission of the arbiter a player is forbidden to have a mobile phone or other electronic means of communication in the playing venue, unless they are completely switched off. If any such device produces a sound, the player shall lose the game. The opponent shall win. However, if the opponent cannot win the game by any series of legal moves, his score shall be a draw.