Re: Logical AND, OR, XOR operators inside ifeq ... endif construct condition.

[Ken Smith]

On Fri, Oct 28, 2005 at 03:28:45PM -0400, Paul D. Smith wrote:
> %% "Boucher, Jean" <address@hidden> writes:
> 
>   bj> Also, one of the situation I'm trying to test for is the empty
>   bj> string (in my previous example, say Y=`'), which I believe I can't
>   bj> test in this manner:
> 
>   bj>     ifeq ($(var),$(filter $(var),X `'))
>   bj>         ...
>   bj>     endif
> 
> Nope, you can't do that.  Hm.  That's tricky, because the empty string
> in GNU make means "false".
> 
> You can use $(if ...)... a bit strange with an if function inside an
> ifeq, but it would work.  You'd have to write it specially: using the
> GMSL version John created I don't think will work because the value
> you're comparing it to is itself false.
> 
> Something like this would work I think (untested):
> 
>     ifeq ($(var),$(if $(var),$(filter $(var),X),$(var)))

You may be able to get by with this if conditional 1 and conditional 2
are mutually exclusive or Action is not sensitive to multiple
execution.

1)
define Action
  the
  stuff
  you 
  want
  to
  do
endef

ifeq (conditional 1)
  $(Action)
endif

ifeq (conditional 2)
  $(Action)
endif

  Ken