[JimmyCh]

If you want it just like that like the one you showed us, it's this:

pawn Код:

forward OnPlayerCommandPerformed(playerid, cmdtext[], success);
public OnPlayerCommandPerformed(playerid, cmdtext[]), success)
{
    if(!success) return SendClientMessage(playerid, -1, "{F20A0A}Error: {FFFFFF}That command doesn't exist, type /help for a list of commands.");
return 1;
}