The problem is that there is no general agreement about where to put libraries on Linux and most 64-bit Linux distros support running 32-bit programs using libraries in a different directory from the 64-bit ones.
On 32-bit Debian, /usr/lib is likely to contain 32-bit libraries. On 64-bit Debian, /usr/lib is likely to contain 64-bit libraries. On 32-bit and 64-bit Fedora, /usr/lib is likely to contain 32-bit libraries.
Many libraries on later Ubuntu distros are in platform-specific directories such as /usr/lib/i386-linux-gnu and /usr/lib/x64_x86-linux-gnu
Therefore, the path you need depends on whether you are running a 64-bit Lisp, a 64-bit OS and also on which distro you are running. In particular, /usr/lib might give you the wrong libraries.
__Martin
On Sat, 5 Apr 2014 16:48:31 -0400, Liam Healy said:
I'm uncertain what you mean, all that #+unix adds is /usr/lib and /usr/local/lib. How is that Debian-specific? Can you suggest better paths for #+unix, or #+linux if you want? I noticed the Solaris "64" and "amd64" inconsistency, but I'm not a user of Solaris so I don't know what's right.
Moreover: all those paths come from actual paths used in quicklisp projects. Presumably, if it works for users of those projects, it works for all users of all projects on those platforms. Conversely, if it doesn't work, it needs to be fixed everywhere. This supports the idea of putting it in a central place; it is already getting more visibility than the discussions on project mailing lists.
On Mon, Mar 31, 2014 at 1:24 PM, Martin Simmons martin@lispworks.comwrote:
> On Sun, 30 Mar 2014 09:41:08 -0400, Liam Healy said:
From time to time I have seen requests from users to include an absolute path (starting from "/") in systems that use load-foreign-library under a clause for their favorite OS. This makes me nervous, especially when it
is
a little-used OS, because I have the feeling the requester's
configuration
is not typical for that OS and I will later get a request to add a different path when the original requester has moved on.
Ideally, there would never have to be any absolute paths; dlopen would always know where to find libraries, because the OS is always configured
in
a standard way. However, a quick survey of this topic shows that reality falls far short of this ideal, and remedies are not clear. It is well beyond our capabilities to fix the entire world on this matter.
Between fixing the world and fixing every CFFI-using application one by one, there is the compromise of setting default search paths for each OS
in
CFFI itself, thereby opening all applications to proper functionality out of the box for most OSes. The variable cffi:*foreign-library-directories* seems like the right thing to set. I've looked through all Quicklisp libraries for absolute paths in uses of load-foreign-library, and found these:
Solaris: /lib/64, /usr/lib/amd64, /usr/lib Darwin: /usr/lib, /opt/local/lib, /usr/local/lib Unix: /usr/local/lib, /usr/lib
Therefore I propose to change the definition to:
(defvar *foreign-library-directories* '(#+(or unix darwin solaris) "/usr/lib" #+(or unix darwin) "/usr/local/lib" #+darwin "/opt/local/lib" #+solaris "/lib/64" #+solaris "/usr/lib/amd64") "List onto which user-defined library paths can be pushed.")
As requests come in to add an absolute path for an application, they can
be
referred to this mailing list to request the change here, if it is not an application-specific path. Then it is more likely to be properly vetted
for
general applicability for all users of that OS, and will be available for all libraries. Does this sound like a reasonable way to handle this
problem?
I think your proposed unix (Linux) clause assumes a Debian-style split between 32-bit and 64-bit. This will be wrong when using a 32-bit Lisp on 64-bit Debian/Ubuntu and also wrong when using a 64-bit Lisp on 64-bit Fedora/RHEL/CentOS.
I'm also not sure about the Solaris cases. It should probably be /usr/lib/64 instead of /usr/lib/amd64, though it may also be wrong to add them for a 32-bit Lisp.
__Martin
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