Re: [Boost-build] Call of interest

Subject: Re: [Boost-build] Call of interest
From: Vladimir Prus (vladimir_at_[hidden])
Date: 2009-05-28 13:05:41

Konstantin Litvinenko wrote:

> Vladimir Prus пишет:
>>>     If Jam has that feature then its implementable. So why stick with
>>> Jam only because Jam has it? Yes, it is require implement/test that
>>> functionality. But I don't scare by that - I will do it and will have
>>> that feature along with those Jam don't have.
>> 
>> I don't claim that this feature is extra hard to implement and you won't
>> ever implement it. All I am saying is that until that feature is available,
>> we won't be able to consider using your build engine for boost.build.
> 
> Ah, I understand. Well, I will try to implement this feature as soon as
> possible :).
> 
>   While
>> that's not your primary purpose, that would be handy.
>> 
>>>> I mean, if a.o was produced from a.cpp, will a.o be rebuild if:
>>>>
>>>> 1. a.cpp time changes, while content does not.
>>> Yes
>> 
>> How hard would it be to make Hammer compute MD5 signature of a.cpp
>> content and use *that* to decide if update is necessary.
> 
> Hm. Don't know right now. Checker is separate part and has 150 LOC, so I
> think it is not to hard to implement another one. But I am curious why
> to use MD5 for that? I saw SCons do that, but don't get it why. Why use
> all this cryptographic and not relay on timestamp? Is there a *real*
> benefit?

Well, if you change a file, save, and then realize the change is bad
idea and revert, you probably don't want a rebuild.

- Volodya