is it problematic to "call" a non-existent define?

  is there any problem with invoking $(call fred) if
"fred" hasn't
been defined?  that is, is "call" defined to just
quietly pass over
that and keep going?  thanks.

rday

============================================================
============
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

http://crashcourse.ca
============================================================
============


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On 21 December 2007 21:55, Robert P. J. Day wrote:

>   is there any problem with invoking $(call fred) if
"fred" hasn't
> been defined?  that is, is "call" defined to
just quietly pass over
> that and keep going?  thanks.

  No problem at all, and yes, if you call an undefined
variable, it expands to
nothing - which of course is then unchanged by applying the
arguments since it
doesn't contain any $(1) etc.  You'll get a warning message
if you've used
"--warn-undefined-variables" on the command line.

    cheers,
      DaveK
-- 
Can't think of a witty .sigline today....



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On Sat, 22 Dec 2007, Dave Korn wrote:

> On 21 December 2007 21:55, Robert P. J. Day wrote:
>
> >   is there any problem with invoking $(call fred)
if "fred" hasn't
> > been defined?  that is, is "call"
defined to just quietly pass over
> > that and keep going?  thanks.
>
>   No problem at all, and yes, if you call an undefined
variable, it expands to
> nothing - which of course is then unchanged by applying
the arguments since it
> doesn't contain any $(1) etc.  You'll get a warning
message if you've used
> "--warn-undefined-variables" on the command
line.
>
>     cheers,
>       DaveK

i suspected as much, i was just curious if it was a standard
make
technique to do that sort of thing.  thanks.

rday
--

============================================================
============
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA

http://crashcourse.ca
============================================================
============


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