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Meaning of the following make snippet INSTALLSOURCE=$(subst /,\,$(DEST))

I am trying to understand some code in the makefile and I came across the below snippet --

export INSTALLSOURCE=$(subst /,\,$(DEST))

I read that subst is used to substitute certain values but what does the above snippet actually do, will be good if someone can explain with an example

Solution

  • It's substituting / with \ in $(DEST). That is, in the content of the DEST variable. Then all of this is assigned to INSTALLSOURCE.

    For further reading, please refer to the doco on subst.

    Borrowing the example from the GNU doco:

    $(subst ee,EE,feet on the street)

    Changes:

    FROM: "feet on the street"
TO:   "fEEt on the strEEt"

    But in your case, if DEST was:

    /path/to/file.txt

    It becomes:

    \path\to\file.txt