Does your company place comment header blocks claiming copyright/trade secret/ etc. to all source code files?
If so, what is your policy on doing so? Do you claim copyright/trade secret for ALL source code files or do you claim copyrights for all and Trade Secrets for only those that contain Trade Secrets?
Can you post sample comment blocks with the legalese and how you arrived at it?
I bring this up, because some time ago, when i worked for IBM, there were specific instructions on what to put in the legal part of software headers that seemed to make a lot of sense. There were different levels of protection to claim. The lowest being publicly available in which case you would provide a standard "AS-IS"/"No Warranty"/"Free"/"Leave this message" provisions. The next level claimed Proprietrary/Confidential and stated that only explicitly authorized individuals are allowed access (and that if an employee/contractor ends their relationship, they must return/delete/destoy/etc. The highest claimed that the contents were Trade Secrets and went even further.
I know that is is not strictly a programming question, but I can't think of a better place to survey what real developers do and possible get folks to post their policies and even sample headers (omitting company names, etc.)
I will start by posting the one that I am using as an answer. I built it by running searches on Google Code (oddly and ironically there are lot's of such header publicly available there) and then taking what seemed to be the best stuff from each.
My hope is that the SO community can vote up/down and add comments to each answer and we can evolve to a best practice that others can follow.
If this is best as a community wiki, I am 100% fine with that. I will let someone else make that determination.
Answer
Here is the one that we use universally in all of our proprietary code:
///
/// [COMPANY NAME] LLC ("COMPANY") CONFIDENTIAL
/// Unpublished Copyright (c) 2009-2010 [COMPANY NAME], All Rights Reserved.
///
/// NOTICE: All information contained herein is, and remains the property of COMPANY. The intellectual and technical concepts contained
/// herein are proprietary to COMPANY and may be covered by U.S. and Foreign Patents, patents in process, and are protected by trade secret or copyright law.
/// Dissemination of this information or reproduction of this material is strictly forbidden unless prior written permission is obtained
/// from COMPANY. Access to the source code contained herein is hereby forbidden to anyone except current COMPANY employees, managers or contractors who have executed
/// Confidentiality and Non-disclosure agreements explicitly covering such access.
///
/// The copyright notice above does not evidence any actual or intended publication or disclosure of this source code, which includes
/// information that is confidential and/or proprietary, and is a trade secret, of COMPANY. ANY REPRODUCTION, MODIFICATION, DISTRIBUTION, PUBLIC PERFORMANCE,
/// OR PUBLIC DISPLAY OF OR THROUGH USE OF THIS SOURCE CODE WITHOUT THE EXPRESS WRITTEN CONSENT OF COMPANY IS STRICTLY PROHIBITED, AND IN VIOLATION OF APPLICABLE
/// LAWS AND INTERNATIONAL TREATIES. THE RECEIPT OR POSSESSION OF THIS SOURCE CODE AND/OR RELATED INFORMATION DOES NOT CONVEY OR IMPLY ANY RIGHTS
/// TO REPRODUCE, DISCLOSE OR DISTRIBUTE ITS CONTENTS, OR TO MANUFACTURE, USE, OR SELL ANYTHING THAT IT MAY DESCRIBE, IN WHOLE OR IN PART.
///
NOTE: this has been reviewed by legal counsel - we are US based.