Information on configuring an external diff/merge tool can be found in
The arguments for comparing two files or two versions of a file should be:
/t1=%bname /t2=%yname %base %mine
With this command line, “original version (%bname)”
will be in the left panel and the “modified version
(%mine)” will be in the right panel. . If you want to limit yourself to
strictly viewing, rather than editing, the changes, add
/ro2 to the beginning
of the above command line.
The arugments for merging two versions of a file from a common ancestor should be:
/m /r=%merged /t1=%yname /t2=%bname /t3=%tname /c=%mname %mine %base
With this command line, “your changes (%mine)” will be in the left panel, the “common ancestor (%base)” will be in the center panel, and “their changes (%theirs)” will be in the right panel. When you save your merge changes, they will be written to the “merge result (%merged)” file.