makefiles: obj vs. objtree

makefiles: obj vs. objtree

[Randy Dunlap]

Can someone clarify the difference(s) in these variables, please?

Documentation/kbuild.txt says about objtree:

$(objtree) is the directory where output files are saved.
The output directory is often set using "O=..." on the commandline.


Documentation/makefiles.txt says about obj:

    $(obj)
	$(obj) is a relative path which points to the directory
	where the target is saved. Always use $(obj) when
	referring to generated files.


These appear to be the same to me, but let me be more specific:

In some cases (or places), Documentation/DocBook/Makefile uses
$(obj) and other cases/places, it uses $(objtree).
Does it have these correct, or should some of them be fixed?

thanks,
-- 
~Randy

Re: makefiles: obj vs. objtree

[Michal Marek]

On 18.2.2010 03:27, Randy Dunlap wrote:
> Can someone clarify the difference(s) in these variables, please?
> 
> Documentation/kbuild.txt says about objtree:
> 
> $(objtree) is the directory where output files are saved.
> The output directory is often set using "O=..." on the commandline.
> 
> 
> Documentation/makefiles.txt says about obj:
> 
>     $(obj)
> 	$(obj) is a relative path which points to the directory
> 	where the target is saved. Always use $(obj) when
> 	referring to generated files.
> 
> 
> These appear to be the same to me, but let me be more specific:

$(objtree) is the toplevel build directory (as the doc says the
directory you specify with O=).
$(obj) is the directory below $(objtree) where the targets of the
current Makefile are saved:

$ make O=/build/dir
$(objtree) == /build/dir
$(obj) == /build/dir/fs in fs/Makefile


> In some cases (or places), Documentation/DocBook/Makefile uses
> $(obj) and other cases/places, it uses $(objtree).
> Does it have these correct, or should some of them be fixed?

$(objtree)/Documentation/DocBook could be written as $(obj) in
Documentation/DocBook/Makefile.

hth,
Michal

Re: makefiles: obj vs. objtree

[Randy Dunlap]

On 02/18/10 01:54, Michal Marek wrote:
> On 18.2.2010 03:27, Randy Dunlap wrote:
>> Can someone clarify the difference(s) in these variables, please?
>>
>> Documentation/kbuild.txt says about objtree:
>>
>> $(objtree) is the directory where output files are saved.
>> The output directory is often set using "O=..." on the commandline.
>>
>>
>> Documentation/makefiles.txt says about obj:
>>
>>     $(obj)
>> 	$(obj) is a relative path which points to the directory
>> 	where the target is saved. Always use $(obj) when
>> 	referring to generated files.
>>
>>
>> These appear to be the same to me, but let me be more specific:
> 
> $(objtree) is the toplevel build directory (as the doc says the
> directory you specify with O=).
> $(obj) is the directory below $(objtree) where the targets of the
> current Makefile are saved:
> 
> $ make O=/build/dir
> $(objtree) == /build/dir
> $(obj) == /build/dir/fs in fs/Makefile
> 
> 
>> In some cases (or places), Documentation/DocBook/Makefile uses
>> $(obj) and other cases/places, it uses $(objtree).
>> Does it have these correct, or should some of them be fixed?
> 
> $(objtree)/Documentation/DocBook could be written as $(obj) in
> Documentation/DocBook/Makefile.
> 
> hth,

Yes, it does.  I get it.  Thanks.

-- 
~Randy