ActiveMQ-CPP, libtool and packaging notes

This page attempts to summarise information to be considered

Product version numbers

SONAME

At runtime (when dynamic linking occurs) the SONAME embedded in the library must match the SONAME expected by the application.
To see the SONAME embedded in the library, objdump -p libactivemq-cpp-2.1.2.so | grep SONAME
To see the SONAMEs expected by an application, objdump -p | grep NEEDED
By default, libtool will use the library filename as the SONAME
Libtool’s default behaviour can be modified by the soname_spec variable
Possible SONAMEs fro ActiveMQ CPP:
- libactivemq-cpp-2.1.2.so.0 (each executable will depend on a specific build and will refuse to work with any other build)
- libactivemq-cpp.so.0 (only one version can be installed at the same time)
- libactivemq2-cpp.so.0 (so that 2.x and 3.x can be installed simultaneously)

libtool -release

the -release argument tells libtool the release number
the release number could be the major version number, the complete version number, or the SVN revision number
libtool believes that any two releases are NOT compatible - for example, if an executable expects release number 5, and the library has release number 4 or 6, the executable will refuse to run

libtool -version-info current:revision:age

Allows binary compatibility between versions
The number at the end of the filename is the interface version number
Interface version number is NOT THE SAME as the product version number
Interface version number should increment each time the `interface’ changes (new function prototypes, new function arguments, change in wire protocol, etc)
The `age’ number is used to indicate backwards compatibility - if age=1, then this interface is backwards compatible with the previous version only, if age=2, then this interface is backwards compatible with the 2 previous versions

Debian package name

The package name includes the following from libtool: release number and interface number
for example, if interface version = 4, then the package name = libactivemq-cpp4
The product version number is not part of the Debian package name - it is used elsewhere in Debian’s control files