[Boost-build] Misleading error message after failing to find boost-build

From: Paul A Bristow (pbristow_at_[hidden])
Date: 2006-05-23 07:16:32

A few Notes on using bjam v2

Most MSVC users are NOT regular command Prompt users, so they need their
hands held quite firmly!

Examples of everything would make many thing MUCH clearer,
for example using the default locations.

1  I had some trouble with the meaning of 

Boost.Build v2 root directory

#edit to point to your BOOST_ROOT:

I expected this to mean the directory ***above*** \boost_1_NN_nn

I think you should say BOOST_BUILD_V2_ROOT here to avoid any confusion?
(Or am I terminally confused?)

example "c:\program files\boost\boost_1_34_0\tools\build\v2"

Remind about the quotes if name has spaces in it?
(Spaces in names were always a daft idea)

set BOOST_BUILD_PATH = "c:\program files\boost\boost_1_34_0\tools\build\v2"

Enter

set BOOST_BUILD_PATH

and it should show the expected location if done correctly.

Remind users that this will need changing when each new release is
installed?

2  editing user and site-config files.

Suggest that users save a copy of the original files before editing them?

Does one not have to specify the MSVC version?

3  Having done this (correctly)

I:\boost-06-05-03-1300\libs\math>set boost_build_path
BOOST_BUILD_PATH= I:\boost-06-05-03-1300\tools\build\v2

I got this message still whatever I did:

I:\boost-06-05-03-1300\libs\math>bjam --v2 test
Unable to load Boost.Build: could not find build system.
---------------------------------------------------------
I:\boost-06-05-03-1300\libs\math\boost-build.jam attempted to load the build
sys
tem by invoking

   'boost-build ../../../develop/boost/tools/build/v2 ;'

but we were unable to find "bootstrap.jam" in the specified directory
or in BOOST_BUILD_PATH (searching
I:\boost-06-05-03-1300\libs\math\../../../deve
lop/boost/tools/build/v2,  I:\boost-06-05-03-1300\tools\build\v2).

Please consult the documentation at 'http://www.boost.org'.  <<< not very
helpful!! - better to be more specific?

I:\boost-06-05-03-1300\tools\build\v2\boostrap.jam appeared to exist?

Eventually traced this to need to change a **local** .jam BOOST_ROOT
definition:

The specification for this was to a sub-directory that did not exist on my
system :-(

BUT the error message mislead me - it was NOT a problem with finding
bootstrap.jam,
but instead with finding boost_build.

This must be a fairly frequent mistake that users will make,

So perhaps an "if booost_build does not exist" then 
error message like
"boost-build.jam could not be found to load the build system"

would avoid wasting an unhappy hour or so :-((

4  The --version option is missing from the jamfile.v2 #usage "help" in
comments.

This command is most useful to check that bjam is installed OK, the first
hurdle!

Suggest that users do this?

Paul Bristow 22 May 2006