Re: [boost] Getting started build section

Subject: Re: [boost] Getting started build section
From: David Abrahams (dave_at_[hidden])
Date: 2008-11-06 09:38:02

on Thu Nov 06 2008, Vladimir Prus <ghost-AT-cs.msu.su> wrote:

> Dave,
> I am reading the getting started guide, and think some of the build
> instructions can be improved. I can do this myself, if we agree on
> the nature of the changes.
>
> For reference, I'm looking at:
>
> 	http://www.boost.org/doc/libs/1_37_0/more/getting_started/windows.html
>
> 5   Prepare to Use a Boost Library Binary
>
> 	I think the section title is too long-winded. "Prepare" does not even
> 	suggest any kind of building.  And of course, we have many libraries,
> 	so saying "a ... Binary" is not accurate.
> 	Would "Building Library Binaries" be more to the point?

No.  You may have used the installer.

>
> The installers supplied by BoostPro Computing will download and install pre-compiled
> binaries
> into the lib\ subdirectory of the boost root, typically 
> C:\Program Files\boost\boost_1_37_0\lib\. If you installed all variants of the
> Boost.Regex binary,
> you're done with this step. Otherwise, please run the installer again and install them
> now.
>
> 	I can't understand what the second sentence say. If installer allows to
> install only
> 	some variants of Boost.Regex, then documentation should to request the user to
> run
> 	the installer again, and install the remaining ones. I can't fix this text
> without
> 	knowing what it means.

Umm, that's exactly what it means.  There's nothing to fix.

>
> 5.2   Or, Build Binaries From Source
> If you're using an earlier version of Visual C++, or a compiler from another vendor, 
> you'll need to use Boost.Build to create your own binaries.
>
> 	Earlier than what? No version of Visual C++ is mentioned in the preceding
> text.

Good point; 

>
> Boost.Build is a text-based system for developing, testing, and installing 
> software. To use it, you'll need an executable called bjam.
>
> 5.2.1   Get bjam
> bjam is the command-line tool that drives the Boost Build system. To build Boost
> binaries,
> you'll invoke bjam from the Boost root.
>
>
> 	The last sentence of 5.2 and the first sentence of 5.2.1 essentially duplicate
> each
> 	other. 

No; 5.2.1 makes it clear you'll be using bjam from the command-line and
explains its role in the process.  For example, it's not just something
that sets up your environment or post-processes library files.

> Besides, bjam does not really drives Boost.Build (just like my car
> does not drive me, usually).

Umm, right.  Lots of terms we use in CS don't map meaningfully onto
everyday objects.  How would you characterize bjam's role in the system?

> First, find the toolset corresponding to your compiler in the following table.
>
> 	The kylix should be removed from the table. 

Have we dropped it?

>       "FreeScale" should be "Freescale".

Good point; 

> 	This should also link to the list of toolchains in Boost.Build docs.

Exact link, please.

> 5.2.3   Select a Build Directory
> Boost.Build will place all intermediate files it generates while building into 
> the build directory. If your Boost root directory is writable, this step isn't
> strictly
> necessary: by default Boost.Build will create a bin.v2/ subdirectory for that 
> purpose in your current working directory.
>

> 	I suggest that this section be dropped. In describes a non-mainstream usage
>       that is better be describe elsewhere. 

Maybe, but the thing I worry about is that a suitable "elsewhere"
doesn't exist.  People seem to expect the GSG to tell them all sorts of
things that perhaps should be in a Boost.Build guide.  I think that's
because they are having a hard time making the jump to that documentation.

>       FWIW, the case of building source straight
> 	from CD does not seem reasonable, since with large number of headers the
> 	performance will be horrible. 

True.

>       Likewise, building from a network drive is not
> 	a good idea. 

Why?  I know companies where people do that successfully.

>       So, copying source to a local drive and building from there is
> 	the best thing.
>
> bjam --build-dir=build-directory --toolset=toolset-name --build-type=complete stage
>
> 	Per above, I suggest we drop --build-dir. --toolset= should
> 	become toolset=

Sorry, I thought I had changed the --toolset= business already.

> 	This section should also link to Boost.Build doc section about command line
> 	syntax.

Exact link, please.

>
> 5.3   Expected Build Output
>
> 	This section fails to mention the single most important point -- that
> 	the libraries are produced, and where they are produced. In fact, I
> 	don't see an obvious purpose of this section to the user -- it just
> 	says "oh, and those kinds of message appear". 

The purpose is to help all the people who have told us over the years
that they get gobs of messages and they don't know how to tell whether
everything worked or not.  People have been confused by the ICU and
Python-related messages.  People have been confused by the number of
targets built/skipped messages.  People have been confused and upset by
the long pathnames they are seeing; at least telling them that they're
normal eliminates much of that effect.

> 	This section fails to explain what is produced as result -- like that
> 	libraries will be placed in the 'stage' directory.

That's certainly important.

> 	I'd suggest rewording the section like this:
>
> 	5.3 Interpreting the results.

I like the new section title.

> 	The build process produces a large number of output during compilation,
> 	including diagnostic messages from Boost.Build, names of files being
> 	compiled and messages from the compiler. A summary is printed at the end.

I would want to clarify "a summary is printed at the end" so the reader
doesn't think we mean that we summarize these messages at the end of the
document she is reading.

> 	If the summary does not include any failed targets, your build is successful,
> 	and the library binaries can be found in the 'stage' directory. 

"the 'stage' directory" is too imprecise.  How will the reader find it?

>       Otherwise,
> 	you can browse the output to see which libraries failed to build, and which
> 	compile errors were produced.  You can also run bjam again, with the same
> 	option, to try compiling the failed files again.
>
> 	A the beginning of the build, you will be informed what functionality
> 	of C++ Boost libraries is disabled because of lack of required third party
> 	libraries. 

I think lacking a 3rd-party library is not the only reason the functionality
might be disabled.  Don't you need some environment variables set for
ICU, or something?

>       You might want to check that you don't require the disabled
> 	functionality, and perform additional configuration (see individual libraries
> 	documentation).
>
> 	
> If it seems like the build system can't find your compiler and/or linker, 
> consider setting up a user-config.jam file as described in the Boost.Build
> documentation.

Exact link please.

> 	This should have a link to Boost.Build section about configuration, not to the
> top-level
> 	docs.

I think you raise a number of good points above.  Certainly I welcome
more participation from the Boost.Build team in ensuring a smooth
Getting Started experience.  In particular, I think helping people
transition from the GSG to the Boost.Build documentation is crucial.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com