DYLD_LIBRARY_PATH / LD_LIBRARY_PATH的替代品

Question

I'm developing python C++ extensions for use in both OSX and linux. Currently, I can run my code with a wrapper script wrapper.sh :

#!/bin/bash                                                                                                                              
trunk=`dirname $0`                                                                                                                       
trunk=`cd $trunk; pwd`                                                                                                                   
export DYLD_LIBRARY_PATH=$DYLD_LIBRARY_PATH:$trunk/lib                                                                                   
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$trunk/lib/:$trunk/src/hdf5/lib/:$trunk/src/python/lib                                           
$trunk/src/python/bin/python "$@" 

which is able to set up my run like this: wrapper.sh app.py

What I would like to do is to eliminate the need for wrapper.sh , so I need alternatives for DYLD_LIBRARY_PATH and LD_LIBRARY_PATH. I can not put my libraries in some standard location like /usr/local/lib because on my machine, I maintain several independent instances of my libraries. That is, my libraries need to be kept somewhere relative to my installation path. I can't put these environment variables in my login script for the same reason. Currently, I need to call one of my wrapper.sh scripts to use the associated libraries. My goal is to be able to run merely app.py , which if it lives in my installation path, should be able to find its associated python and libraries. The purpose is to simplify execution for users, and to simplify usage of external tools like nosetests.

One alternative seems to be using rpath when I build my version of python:

./configure --enable-shared --prefix=$(CURDIR)/$(PYTHON_DIR) LDFLAGS="-Wl,-rpath,$(CURDIR)/lib/ -Wl,-rpath,$(CURDIR)/src/hdf5/lib -Wl,-rpath,$(CURDIR)/src/python/lib"

This trick seems to work fine on linux, even though one of my libraries ended up needing to be copied directly into trunk/src/python/lib/python2.6/lib-dynload for some reason unclear to me. However, this trick is not working on OSX; it looks like I need to run install_name_tool on all my dylibs libraries.

The other alternative I came up with was to do something like this:

ln -s wrapper.sh python

so that my scripts could all use #! ../python #! ../python , but I'm getting Unmatched ". errors. Same thing if I use #! ../wrapper.sh . I'm not really an expert in bash...

However, these all seem so unnecessarily complicated, and surely this is something that other people have solved?? Thanks for any advice!

Answer 1

For python extensions, consider using PYTHONPATH: the Python interpreter will search the PYTHONPATH for .py/.pyc/.pyo/.so modules, as well as packages. See docs for Python 2.x as well as docs for Python 3.x ; specifically the section named "The Module Search Path" on both pages. This also references information that seems to indicate that it is possible to update the module search path at runtime, which, if true, means that you could add all that logic to your program and it can hunt for its libraries on its own (say if it installs a copy in /usr/libexec/pkgname/... somewhere or something).

For all but the most complex of cases, though, setting PYTHONPATH and using a shell-script or native-compiled binary wrapper to start the core program is an okay approach, and one that is also used in other language environments including Mono and Java.

Answer 2

Not sure if this would be an acceptable (partial) solution in your circumstances, but another way to get libraries noticed by ld on linux is to add the path to the libraries to /etc/ld.so.conf and then run ldconfig

For the Mac I don't remember the details, but I think Apple provide some resources for distributing apps packaged as a .app which includes some default locations (relative to the root of the .app) for libraries, or "frameworks" as they call them. Would require some googling from there - sorry can't help further on that but hope you get some progress :-)