Re: setting a variable only on condition that a rule is applied?

[Paul D. Smith]

%% David Wuertele <address@hidden> writes:

  dw> Can I set a variable only on condition that a rule is applied?  For
  dw> example:

If you have GNU make 3.80 you can say:

  dw> dorule1:
  dw>   @echo in rule1
  dw>   RULE_DEPENDENT_VAR+=rule1text

Of course this won't work, because text after a TAB is the command
script and is passed to the shell to be evaluated.  The shell tries to
run a command named "RULE_DEPENDENT_VAR+=rule1text" and fails.

 dorule1:
        @echo in rule1
        $(eval RULE_DEPENDENT_VAR+=rule1text)

Note that this setting will happen as soon as make decides to run this
command, not after it runs the first line successfully.


Personally I'd probably just create a manifest file, something like:

 dorule1:
        @echo in rule1
        @echo rule1text >> MANIFEST


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