Re: pkg() in 4.0.0-rc1 breaks building of some packages

[Juan Pablo Carbajal]

On Tue, Mar 10, 2015 at 2:37 PM, Mike Miller <address@hidden> wrote:
> On Tue, Mar 10, 2015 at 08:30:34 +0100, Olaf Till wrote:
>> Thought I mention it here before making a regular bug report, since it
>> might be release-critical.
>>
>> Private function configure_make() of pkg() now calls 'make' with the
>> '--jobs' option, enabling parallel builds. This should only be done in
>> cases in which certain design rules are followed in package
>> Makefiles. Currently it breaks at least building the parallel package:
>>
>> I've  the following lazy, stupid, and inefficient rule in this
>> Makefile, which of course should be changed, but which is nevertheless
>> legal:
>>
>> %.oct: %.cc
>>       @MKOCTFILE@ -s -v $< sock-stream.cc
>>
>> This causes sock-stream.cc to be compiled to sock-stream.o for each
>> built oct-file. make --jobs .. builds the oct-files in parallel, so it
>> happens that one job is just about to (over-)write sock-stream.o when
>> another job uses it for linking, causing the linking to fail.
>>
>> Before I supply a (trivial) patch, it should probably be decided
>> whether the --jobs option should be just removed or made an option of
>> pkg(), defaulting to non-parallel building.
>
> There should be a couple of other ways to address this without changing
> pkg.
>
> As the end user, you can call `setenv OMP_NUM_THREADS 1` in the Octave
> shell before doing the pkg install, that should translate to --jobs=1.
> So in this sense it is already an option that the end user has control
> over.
>
This is good to know! but as you see, it is not cristal clear for
everybody. I think pkg() could be more useful if it provided a
solution...maybe just calling the line you just provided.

I personally think pkg() needs a refactoring and I was involved in it
while it lasted. I will behappy to give it another go if we believe
pkg() will be the "inside octave" tool for the user to handle
packages.

> In the package Makefile, you should be able to use the .NOTPARALLEL
> special target to have your build ignore the --jobs setting.
>
> HTH,
>
> --
> mike
>