[C++-sig] How to install extensions using bjam(?)

[Amos Anderson]

On Mon, Oct 26, 2009 at 7:08 AM, Anthony Foglia <AFoglia at princeton.com> wrote:
> Amos Anderson wrote:
>>
>> I'm working on a project which is mixed C++/Python, and we use Boost
>> functionality in our C++, and we've set up bjam to compile our project
>> (on OSX). Everything seems to be working quite well.
>>
>> To use our libraries from python scripts right now, we have to run this
>> first:
>>
>> #!/bin/bash
>> trunk=$HOME/project/trunk/
>> export DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH:$trunk/lib
>> export PYTHONPATH=$trunk:$trunk/lib
>> python $@
>>
>>
>> which is quite inconvenient. Now obviously I can skip this step by
>> pasting those two export statements into my .profile, however, at some
>> point we're going to start distributing this software and it would be
>> nice if we didn't require the end user to do something like that.
>>
>> I can't believe that either of these 2 steps are how it's supposed to
>> work... so how should I be doing it?  Ideally, I want to set something
>> up so that the end user only has to run 1 (one) command to build &
>> install. Here are some things I've thought about:
>
> [...]
>
>> 3) bjam includes a way to install libraries into a folder I can name,
>> but does it have a way to set environment variables? or automatically
>> figure out the right places to put all the python files? If so, I
>> can't find it...
>
>        Almost certainly not.  bjam would be running in a child process and
> won't be able to change the environment of the parent (shell) process. Even
> if it did, any changes wouldn't persist into newly launched shells.


Well, what I had in mind was getting bjam to implement my solution #1.
So bjam would scan my .profile to see if it had ever modified the file
previously, and if so modify previously set variables, otherwise add
new environmental variables, etc.


>
>        I don't think there you can get the "right place" to put the python
> files, especially since different users will have different "right places".
>  I think your best bet is to follow the usual convention of using a default
> location of "/usr/lib/python<version>/site-packages", but allow users to
> override it from the command line.  I'm not 100% sure of the syntax, but
> something like
>
> bjam -s prefix=/usr/local/lib/python2.5
>
> should set the variable prefix to /usr/local/lib/python2.5 inside the
> Jamfile.
>
> Now you just need a way to get the default python version to set the default
> value.  bjam's python module has a .version-countdown variable that might
> help.


Based on your idea, I did some searching, and I found that I can do this:

python -c "from distutils.sysconfig import get_python_lib; print
get_python_lib()"
/Library/Python/2.6/site-packages

to automatically find the right location. And, it looks like:
http://developer.apple.com/mac/library/documentation/Darwin/Reference/ManPages/man1/dyld.1.html
says I can put the dylib's in one of these places:
$(HOME)/lib:/usr/local/lib:/lib:/usr/lib

and the linker will automatically find them. I guess one of those is
good enough for me, but I'd imagine that python would add a few new
places to look? I tried to put my dylib files into site-packages, but
that didn't work.

It looks like this is making some progress. It looks like at the very
least I can get bjam to put the dylib into $(HOME)/lib directly, and
edit the python scripts to add the right python paths.


Amos.


>
> The boost-build mailing list can probably give you better help.
>

I've tried a few times to sign up to that list... but it doesn't seem to work.


thanks!

Amos.



> --
> Anthony Foglia
> Princeton Consultants
> (609) 987-8787 x233
>
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