Re: [boost] --layout=system creates versioned libraries

From: Caleb Epstein (caleb.epstein_at_[hidden])
Date: 2005-06-17 20:03:08

On 6/17/05, Julio M. Merino Vidal <jmmv84_at_[hidden]> wrote:
> Everything went correctly, but then I found more files than expected
> under the stage/lib directory.  These are:
> 
> libboost_filesystem-mt.a
> libboost-filesystem-mt.so (link to libboost_filesystem_mt.so.1.32.0)
> libboost_filesystem_mt.so.1.32.0
> 
> As I understand from the documentation, setting --layout=system during
> the build should cause all libraries to be unversioned (i.e., only the
> .a and .so should be there), although from the above results it seems to
> be working incorrectly in this platform.

No, I believe this is the correct behavior.  Versioned shared
libraries (if used properly) ensure that you can't accidentally pick
up an incompatible (older or newer) version of a library at run time,
even if it has the same name as the one you compiled with.

As a user, you don't need to know you're linking with the .so.1.32.0
version of the library, you just link with -lboost_filesystem-mt, and
your linker takes care of the version binding.

The default --layout behavior adds the Boost version number into the
actual library name (the part *before* .a or .so), which means you
need to link with (say) -lboost_filesystem-gcc-mt-1_32.

> However, trying this same thing under NetBSD/i386 (GCC 3.3.3) resulted
> in the expected files; the .so.1.32.0 was not created, and the .so one
> was a real file, not a link.

Perhaps NetBSD doesn't support versioned shared libraries, or the
Boost.Build plumbing doesn't know how to create them on that platform.

> Any idea about what can be causing this issue?  Am I doing something
> wrong?

No.  I don't think so.

-- 
Caleb Epstein
caleb dot epstein at gmail dot com