Makefile and ifeq

GENERAL Help
1

I have encountered a strange problem with make and ifeq evaluations and $@.

I want to set specific link libraries based on the target the user supplies when running make.

So I did the following in my makefile:

Foo = bar
ifeq ($@,$(Foo))
Lib = “Equal”
else
Lib = “Not equal”
endif

Later on my compile line I echo’d out the results as:

@ echo “Results of compare” “<”$@">" “<”$(Foo)">" $(Lib)

So I issue ‘make bar’ on the command line and get an output of:

Results of compare Not Equal.

No matter what I do, the ifeq always evaluates to Not Equal.

Even if I do something like:

Input = $@
Blah = $(filter bar, $(Input))
Foo = bar
ifeq ($(Blah),$(Foo))
Lib = “Equal”
else
Lib = “Not Equal”
endif

It still comes out as Not Equal even tho Blah prints out as ‘bar’.

Now I know that ifeq is not broken because if I do:

Blah = bar
Foo = bar
ifeq ($(Blah),$(Foo))
Lib = “Equal”
else
Lib = “Not Equal”
endif

This does evaluate to Equal.

So I’m very very confused about how Make is treating the $@ parameter when converting it to a string. Esp since it can filter out bar part but yet it can’t make the two strings manage to be equal.

Anyone have any idea what’s up with this?

TIA,

Tim

2

My guess is you cannot use $@ in a ifeq statement.

As a matter of fact if you do

ifeq ($@,)

you will discover that the result is true, meaning $@ resolves to an empty value.

I don’t understand the rational behind this behavior though. I beleive if statement are performed once, the make is first parsed, hence I don’t think it makes sense to use $@.

3

Mario,

OK, if $@ doesn’t work (even tho you can assign it to a variable as I did with my statement ‘Input = $@’ and Input was set to the value on the command line I expected which doesn’t seem to reconcile with it having a an empty value) then how do you get args passed into a Make command?

I tried $1 which works for scripts and it’s always blank.

Tim

4

Try $(MAKECMDGOALS)

5

Xtang,

Works perfectly!

Thanks,

Tim