Helix Core Server Administrator Guide: Fundamentals (2019.1)

Implementing site-wide exclusive locking with p4 typemap

By default, Helix server supports concurrent development, but environments in which only one person is expected to have a file open for edit at a time can implement site-wide exclusive locking by using the +l (exclusive open) modifier as a partial filetype. If you use the following typemap, the +l modifier is automatically applied to all newly added files in the depot:

Typemap:
        +l //depot/...

If you use this typemap, any files your users add to the depot after you update your typemap automatically have the +l modifier applied, and may only be opened for edit by one user at a time. The typemap table applies only to new additions to the depot; after you update the typemap table for site-wide exclusive open, files previously submitted without +l must be opened for edit with p4 edit -t+l filename and resubmitted. Similarly, users with files already open for edit must update their filetypes with p4 reopen -t+l filename.