Re: do I have to use recursive make to make one target fall on another?

[Eli Zaretskii]

> From: "Mark Galeck (CW)" <address@hidden>
> Date: Fri, 2 Mar 2012 00:31:33 -0800
> 
> I have two goals: goal1 and goal2, and they are both made by the recipe for 
> goal2 (goal1 as a side effect).  I know this recipe does not follow Paul's 
> rules of makefiles, but I can't change it.
> 
> What I need to do, is to efficiently accommodate both goals. That means, 
> whether goal1, goal2, or both are given on the command line, there should be 
> only one call to the recipe for goal2.
> [...]
> What to do? I can't change the rest - the rule for goal2, or the implicit 
> rules.  I have to add something for goal1, that is as fast as possible in all 
> cases.  Do I really have to use recursion??

If goal1 and goal2 have something common in their names, you can use
pattern rules.  This is from the GNU Make manual:

     This pattern rule has two targets:

       %.tab.c %.tab.h: %.y
               bison -d $<

  This tells `make' that the recipe `bison -d X.y' will make both
  `X.tab.c' and `X.tab.h'.  If the file `foo' depends on the files
  `parse.tab.o' and `scan.o' and the file `scan.o' depends on the file
  `parse.tab.h', when `parse.y' is changed, the recipe `bison -d parse.y'
  will be executed only once, and the prerequisites of both `parse.tab.o'
  and `scan.o' will be satisfied.  (Presumably the file `parse.tab.o'
  will be recompiled from `parse.tab.c' and the file `scan.o' from
  `scan.c', while `foo' is linked from `parse.tab.o', `scan.o', and its
  other prerequisites, and it will execute happily ever after.)