Re: unwanted implicit rule

[Paul D. Smith]

%% address@hidden writes:

  cl> You can turn off implicit rules by running GNU make with the -r
  cl> flag...for example:

  cl> $ make -r all

This turns off all _built-in_ implicit rules.  It doesn't turn off any
implicit rules that you define yourself.

I think this is pretty clear in the manual.  If not, please let me know
what you find confusing.

  cl> I *think* you can also turn off the implicit rules by doing this in your
  cl> makefile:

  cl> # turn off magic make rules
  cl> .SUFFIXES:

This turns off all the builtin suffix rules only; it doesn't turn off
the builtin pattern rules.

However, almost all the builtin rules are suffix rules, so this gets
most of them.

  cl> ...although I seem to remember this being slower than using -r
  cl> because GNU make still looks for implicit rules for every target
  cl> (even though you have removed them all).  Anyone know the story?

There is no speed difference; the difference is that setting an empty
.SUFFIXES doesn't get _all_ the builtin rules, just most of them.  The
-r flag gets all of them.

  cl> Of course, now you'll have to explicitly specify any implicit
  cl> rules you were using.

Not so; see above.

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