RE: need help with the Makefile

[ravi_murdeshwar]

Hi john,
I need to detect target platform as one can build the driver for linux 2.6 on 
linux 2.4 kernel OS.

Checking empty variable is working fine and I will put it outside the rule.

% cat t1.mak
ifeq ($(strip $(ARCH)),)
$(error Error: Please set ARCH before running Make) endif

% make -f t1.mak
t1.mak:2: *** Error: Please set ARCH before running Make.  Stop.

Is there any way to suppress the makefile name in the error output. I would 
like to just output as error.
"Error: Please set ARCH before running Make."

I think for all other target platform version checkings, I will need to use 
shell functions.

Thanks ..
-- 
Raviraj Murdeshwar.
408.553.4318

> -----Original Message-----
> From: John Graham-Cumming [mailto:address@hidden
> Sent: Friday, September 09, 2005 4:48 AM
> To: address@hidden
> Cc: address@hidden
> Subject: Re: need help with the Makefile
> 
> address@hidden wrote:
> > a. should I ask user to pass some env variable such as KVER=2.4 or
> KVER=2.6 at the make command line and then check the $(KVER) and setup the
> flags accordingly.
> 
> Well that's one way to do it, if you can't do autodetection of the
> version that you are trying to build.
> 
> > Also is it possible to check for empty variable and exist with some
> error msg like following
> >
> > check_ver:
> >         ifeq ($(strip $(KVER)),)
> >       @echo "Error: Please set KVER"
> >         Endif
> 
> That's not going to work because you've got a tab before ifeq and endif
> which means GNU Make is going to pass them to the shell and those are
> internal GNU Make preprocessor commands.
> 
> My recommendation is not to do the checking of KVER in a rule (because
> that rule might never get run).  Instead just check KVER in the Makefile
> at the start and using $(error) to output the message.
> 
> ifeq ($(strip $(KVER)),)
> $(error Please set KVER before running Make)
> endif
> 
> John.
> --
> John Graham-Cumming
> address@hidden
> 
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