(make.info.gz) Archive Update

 
 11.2 Implicit Rule for Archive Member Targets
 =============================================
 
 Recall that a target that looks like `A(M)' stands for the member named
 M in the archive file A.
 
    When `make' looks for an implicit rule for such a target, as a
 special feature it considers implicit rules that match `(M)', as well as
 those that match the actual target `A(M)'.
 
    This causes one special rule whose target is `(%)' to match.  This
 rule updates the target `A(M)' by copying the file M into the archive.
 For example, it will update the archive member target `foo.a(bar.o)' by
 copying the _file_ `bar.o' into the archive `foo.a' as a _member_ named
 `bar.o'.
 
    When this rule is chained with others, the result is very powerful.
 Thus, `make "foo.a(bar.o)"' (the quotes are needed to protect the `('
 and `)' from being interpreted specially by the shell) in the presence
 of a file `bar.c' is enough to cause the following commands to be run,
 even without a makefile:
 
      cc -c bar.c -o bar.o
      ar r foo.a bar.o
      rm -f bar.o
 
 Here `make' has envisioned the file `bar.o' as an intermediate file.
  Chains of Implicit Rules Chained Rules.
 
    Implicit rules such as this one are written using the automatic
 variable `$%'.   Automatic Variables.
 
    An archive member name in an archive cannot contain a directory
 name, but it may be useful in a makefile to pretend that it does.  If
 you write an archive member target `foo.a(dir/file.o)', `make' will
 perform automatic updating with this command:
 
      ar r foo.a dir/file.o
 
 which has the effect of copying the file `dir/file.o' into a member
 named `file.o'.  In connection with such usage, the automatic variables
 `%D' and `%F' may be useful.
(make.info.gz) Archive Update

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