A gINT library can be secured against user modification except by authorized users.This is also called locking the library. A locked library can be distributed within the organization and used without the risk of your organization’s standard library objects such as reports, blocks, user data items and library tables being modified. However, users can utilize those objects in input and output activities as they would normally.Locking and unlocking involves the creation and referencing of a library lock file. This file is an empty text file in a specified location (ideally on your computer’s hard drive) with a specified name. Any computer with a file of the specified name in the specified location will have full editing rights to the locked library. Computers lacking this file will not. Because this file is the only way to access a locked library, you will want to keep a careful record of the name and location of the required file.
Note: A Locked library will prevent the addition of lookup entries from INPUT by users who do not have access to write to the library file, since this process modifies the library.References - Help Topics- Secure Library (command)