Re: [Boost-build] Boost Jam

From: REH (spamjunk_at_[hidden])
Date: 2008-04-12 08:36:01

Jurko Gospodnetić wrote:
>    Hi REH.
> 
>> Hi.  I just started playing with Boost Jam after using ftjam.  One thing 
>> that I've noticed, that I don't like, it that Boost Jam waits until an 
>> action has completed before displaying its output.
>>
>> I have actions that are very time consuming, and I like to monitor their 
>> output in real time.  ftjam does this, but I would prefer to use Boost, 
>> because is has newer features that I want to take advantage of.
>>
>> Is it possible to modify Boost Jam to display actions' output in real-time?
> 
>    Would be relatively simple to do (modifications to exec*.c modules 
> and possibly output.c), but could you then describe how you expect that 
> output to behave in case of multiple parallel build actions (i.e. when 
> the -j # command-line options is used with # > 1 )?
> 
>    As I see it Boost Jam currently collects each build action output in 
> real-time but displays it only once the action has terminated.
> 
>    Some ideas that pop to mind here:
> 
>      (1.) As it is now - just display action output after the action 
> terminates.
>      (2.) Display the action as it is collected from each action, 
> without considering multiple parallel actions.
>      (3.) If there are no parallel actions then as (2.) and otherwise as 
> (1.).
>      (4.) As (2.) but display the output line-by-line so that lines 
> never contain half output text from one action and half from another but 
> different lines from multiple actions may get mixed up.
>      (5.) As (4.) but give each action an id and display it in front of 
> each line in the output. Possibly not displaying the id in case no 
> parallel build actions are allowed.
> 
>    Anyone else have any other ideas on how this could work? Or which 
> choice is best?
> 
>    Another related issue is how the action output is collected 
> programmatically (i.e. when callbacks containing the action output are 
> called). Should that also be done in real-time? Or should that keep 
> getting called only after an action has completed its work?
> 
>    Since this would affect everyone's build system in ways that I can 
> not imagine, I would not like to change anything without enough 
> thoughts/comments/confirmation from others... so... if you want 
> something done about this - you'll have to keep pushing the issue until 
> 'enough' people agree. :-)
> 

Thanks for responding. I don't need parallel builds, so that is not an 
issue. I am also not expecting the maintainers of Boost Jam to make this 
change. I was planning on just making a local change myself, but I 
haven't had time to dig into the code.

Thanks again,

REH