[Scons-users] Forcing projects to build in order

[Ora]

Hi,

During a few of the build steps the script calls various tools which MUST
be run in a specific directory.  That is not something I can change at this
point.

Each such step is defined as its own builder which changes the directory
and runs the required tool.

However, when running with the '-j' option, Scons tries to run several such
steps in parallel, and therefore, tries to execute commands in the wrong
directory.

I cannot avoid parallelism altogether as it it would make my script run for
so long, it would be useless.
I cannot avoid changing directories.

I wish SCons would handle changing directories properly on its own, but I
understand that's not going to happen.

I am therefore looking for a solution to this problem by partially limiting
parallelism so that the builder steps / projects which change directory
would not be called in parallel with other builders.


Ora

On Thu, Aug 6, 2015 at 7:11 PM, William Blevins <wblevins001 at gmail.com>
wrote:

>
> On Thu, Aug 6, 2015 at 11:09 AM, Bill Deegan <bill at baddogconsulting.com>
> wrote:
>
>>
>>
>> On Thu, Aug 6, 2015 at 8:04 AM, William Blevins <wblevins001 at gmail.com>
>> wrote:
>>
>>> I cannot think of many (if any) good reasons to perform CWD.
>>>
>>> Can you modify your build to work without?
>>> On Thu, Aug 6, 2015 at 10:26 AM, Bill Deegan <bill at baddogconsulting.com>
>>> wrote:
>>>
>>>> Ora,
>>>>
>>>> Why do you want to force build order and/or limit parallelism?
>>>>
>>>>
>>> He is performing "change working directory" commands which cause issues
>>> with parallel builds.
>>>
>>
>> When I run into those I typically do env.Command(target,source,"cd xyz;
>> do actual command")  or wrap said command in a script and run that from the
>> command.
>>
>
> That makes sense.  Keeps the CWD commands outside the SCons context :)
>
>
>>
>>>
>>>> -Bill
>>>>
>>>> On Thu, Aug 6, 2015 at 3:58 AM, Ora <orshalev at gmail.com> wrote:
>>>>
>>>>> Hi,
>>>>>
>>>>> My script builds several different projects which are not necessarily
>>>>> related.   How can I force those projects to build in a certain order?
>>>>>
>>>>> That is, I have three projects: a, b and c.
>>>>> I want 'b' to start building only after 'a' finishes, and for 'c' to
>>>>> start building only after 'b' finishes.
>>>>>
>>>>> This is necessary in order to avoid problems with changing directories
>>>>> during parallel builds.
>>>>>
>>>>> I tried using 'Requires', with every target requiring the target
>>>>> before it.
>>>>> Requires (b, a)
>>>>> Requires (c, b)
>>>>>
>>>>> But that doesn't solve the problem because, if I understood correctly,
>>>>> it only tells Scons that it should finish building 'a' before it finishes
>>>>> building 'b', and doesn't prevent it from compiling both projects at the
>>>>> same time.
>>>>>
>>>>> Any suggestions on how to deal with this issue would be appreciated.
>>>>>
>>>>> Thanks in advance,
>>>>> Ora
>>>>>
>>>>> _______________________________________________
>>>>>
>>>>
>>
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>
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