Showing and merging three way differences

You can also use the Diff/Merge tool to look at three-way differences between files and file versions. One situation where this might come in handy is when you want to merge branch file versions and configurations back into the "main trunk" of a file's version tree.
As an example of viewing/merging three-way differences between versions that are on two different branches, let us assume that a source file called

MoneyTransaction.C has the following version tree:

The latest version on the main trunk is called

HEAD . The latest version on the branch is called HEAD_C . Version 1.2 is the common ancestor of both versions.
Now, you can view the three-way differences between the latest version on the main trunk ( 1.5 ), the latest version on the branch ( 1.2.1.3 ) and the ancestor ( 1.2 ). To do so:

Open the project that contains the configurations you are interested in.
Open the Configuration Manager and press the Update button to load your project's configuration information into the Configuration Manager.
Select

HEAD in the Configuration List and HEAD_C in the Compared To List.
The Change List displays all the changes made on the main trunk and the branch since the ancestor version.
From the Change type drop-down menu above the Change List, choose different branches.
The Change List displays only those version controlled files that have a branch at version 1.2 in their version trees.
From the Change List, select the file whose three-way differences you are interested in.
If you just want to look at the three-way differences, choose Configuration > Show 3- Way Differences.
A Diff/Merge tool appears, in which the three-way differences are displayed.
If you want to merge differences, choose Differences > Merge Differences... command and press the 3-Way Merge button.
A dialog appears and asks you whether you want to check out the file selected in the Change List.
If you have already checked out the file, press No. Otherwise, press Yes.
A Diff/Merge tool appears, in which the three-way differences are displayed.