Info Catalog make: Pattern Rules make: Implicit Rules make: Suffix Rules

make: Last Resort

 
 10.6 Defining Last-Resort Default Rules
 =======================================
 
 You can define a last-resort implicit rule by writing a terminal
 match-anything pattern rule with no prerequisites (Match-Anything
 Rules).  This is just like any other pattern rule; the only thing
 special about it is that it will match any target.  So such a rule's
 recipe is used for all targets and prerequisites that have no recipe of
 their own and for which no other implicit rule applies.
 
    For example, when testing a makefile, you might not care if the
 source files contain real data, only that they exist.  Then you might do
 this:
 
      %::
              touch $@
 
 to cause all the source files needed (as prerequisites) to be created
 automatically.
 
    You can instead define a recipe to be used for targets for which
 there are no rules at all, even ones which don't specify recipes.  You
 do this by writing a rule for the target '.DEFAULT'.  Such a rule's
 recipe is used for all prerequisites which do not appear as targets in
 any explicit rule, and for which no implicit rule applies.  Naturally,
 there is no '.DEFAULT' rule unless you write one.
 
    If you use '.DEFAULT' with no recipe or prerequisites:
 
      .DEFAULT:
 
 the recipe previously stored for '.DEFAULT' is cleared.  Then 'make'
 acts as if you had never defined '.DEFAULT' at all.
 
    If you do not want a target to get the recipe from a match-anything
 pattern rule or '.DEFAULT', but you also do not want any recipe to be
 run for the target, you can give it an empty recipe (Defining
 Empty Recipes Empty Recipes.).
 
    You can use a last-resort rule to override part of another makefile.
 Overriding Part of Another Makefile Overriding Makefiles.
 

Info Catalog make: Pattern Rules make: Implicit Rules make: Suffix Rules