Re: multiple wildcards in a static pattern rule

[Paul D. Smith]

%% Noel Yap <address@hidden> writes:

  ny>   2. using '&&' halves the number of shells per target created;
  ny>      ';' would do the same thing but would have the consequence of
  ny>      allowing the 'cp' to execute if the umask failed.

Actually, this is not so.

GNU make takes advantage of the "as if" rule and avoids invoking a shell
at all if the command to run is "simple enough", where "simple enough"
means there is no redirection, piping, globbing, or shell metacharacters
of any kind.

So, actually, for simple commands like this:

  >> $(ROOT)etc/dir1/%: $(ROOT)etc/dir1/%: %
  >>        cp $< $@
  >>        chmod 644 $@

it will be faster to do it this way since GNU make will fork/exec the
two commands directly rather than invoking a shell to do it.


FWIW! :)

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