The path found by directory search!

[ali hagigat]

4.4.3 How Directory Searches are Performed
4. After processing the prerequisites, the target may or may not need
to be rebuilt:
a. If the target does not need to be rebuilt, the path to the file
found during directory
search is used for any prerequisite lists which contain this target.
In short, if make
doesn’t need to rebuild the target then you use the path found via
directory search.
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After processing the prerequisites and the target does not need to be
rebuilt, every thing is finished!! and why and how the path found
during the directory search is used? The path is used for what rule
when the rule does not need to be processed further?
Thank you to read my question.