CVS can also follow the semantics of Lock/Unlock that most version control systems use, although CVS calls it Edit/Unedit. This feature, however, is not enabled in CVS by default so before you can begin you need to enable Watch.
You can enable Watch using TortoiseCVS when you Make a New Module by enabling the checkbox Check files read-only (on the Options tab). If you wish to enable watch on an existing module, you will need run the following command (using the Command Prompt) on the top level of the module:
cvs watch on
Once Watch is enabled, when performing Checkout or Update the working files will be created as read-only. To change one or more files, select the directory, file or files that you want to modify, right-click on the selection, and choose the CVS Edit menu item. This command works slightly different depending on whether the file is text or binary. For binary files (such as .doc), TortoiseCVS performs an Update on the file and then checks if another user is already editing the file. If this is the case, you will not be allowed to edit it. For text files (such as .txt or .cpp), you may work on the file even if another user is already working on it; in this case, TortoiseCVS will notify you of that fact.
When you are done working on the file or files, Commit them as you would normally. If, however, you decide that you do not want to make changes select the file or files: Right-click on this selection and choose the CVS → Unedit menu item. TortoiseCVS will ask you if you want to revert the file to the original version (thus losing your changes).
If you would like to see which files are currently being edited and by whom, right-click anywhere in Windows Explorer and choose the CVS → Show edited files menu item.