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Make And Conditions

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conditions in Make

Newsgroups: comp.unix.questions

>Can I use conditions in make file?
>
>E.g.:
>
>        [ ${TAG} = tag1 ] && {
>         do this
>         do that
>        }
>
>How can I achive the above behavior?

The action (tab-indented) lines in the file are passed to the shell after a small amount of processing on make's part. To do the above, you need to:

double-up any $'s which are supposed to be interpreted by the shell
end each line of a compound statement with a
pretend that the <\><newline> pair was not there and add semicolons (;s) as needed

you want make to be expanding), then the above example becomes:

[ $${TAG} = tag1 ] && { \
  do this; \
  do that; \
}

just remove one of the $s.)

Ken Pizzini

conditions in Make

Example 1. File: Makefile

test:
        [ $${TAG} = tag1 ] && { \
          echo "action 1!"; \
          echo "action 2!"; \
          }


	!!

$ export TAG=tag1
$ make
[ ${TAG} = tag1 ] && { \
  echo "action 1!"; \
  echo "action 2!"; \
  }
action 1!
action 2!

Conditional Syntax

All instances of conditional syntax are parsed immediately, in their entirety; this includes the `ifdef', `ifeq', `ifndef', and `ifneq' forms.