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Subject: Re: [Boost-build] Very slow Visual Studio 2012 builds
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2013-11-04 21:12:13


On 11/04/2013 05:33 PM, Juraj Ivančić wrote:
> On 4.11.2013. 23:28, Steven Watanabe wrote:
>> A few more:
>> - If a user explicitly specifies a setup script,
>> it should be honored.
> Just tried it and it works, to the extent it works for MSVC setup
> scripts. It will fail, though, if user setup script is doing
> something 'smarter' than merely setting up environment variables,
> i.e. if user expects it to be called from every action.

Is there anything besides environmental
variables that can be set by batch scripts
and which can affect subprocesses? I can't
think of anything off the top of my head,
but I'm hesitant to rule it out entirely.

> I cannot think of a reason why anyone would do that, but for them
> this would be a breaking change.

I don't know why anyone would want that, but
then again, I also don't see why anyone would
want to use a custom script in the first place.

>> - Please use set.difference instead of a raw loop.
> Check.
>> - Make sure that this works with a cygwin built b2
>> (That's what the if ! [] in NT section
>> that you deleted is supposed to be handling.
>> I say "supposed to", because although the batch
>> script will run without errors, the environment
>> changes will be discarded.)
> I played for a while with cygwin built b2. This 'supposed'
> part seems to work OK, quotes around '>nul' and '&&' make
> cmd.exe process the rest of the command, so environment
> is not discarded.

Ah, right.

> I am not sure how to make this 'batch file caching' work on
> cygwin though. AFAICS it boils down to generating a
> simpler (faster) batch file, like Chris is doing. I don't
> think its worth the hassle. Not to me, anyway.

There's no reason that the variables have
to be set up using batch file syntax.
You could split each line at the '=' and
use common.variable-setting-command.

> How about just leaving cygwin to work as it did, and speed up
> msvc?

That works, too. I don't care as long as
it isn't broken.

In Christ,
Steven Watanabe

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