Chapter 8. Shared libraries

57

8.6.1 The

shlibs

files present on the system

There are several places where

shlibs

files are found. The following list gives them in the

order in which they are read by

dpkg shlibdeps

. (The first one which gives the required

information is used.)

debian/shlibs.local

This lists overrides for this package. Its use is described below (see `Writing the

debian

/shlibs.local

file' on page

59

).

/etc/dpkg/shlibs.override

This lists global overrides. This list is normally empty. It is maintained by the local

system administrator.

DEBIAN/shlibs

files in the  build directory 

When packages are being built, any

debian/shlibs

files are copied into the control

file area of the temporary build directory and given the name

shlibs

. These files give

details of any shared libraries included in the package.

7

/var/lib/dpkg/info/*.shlibs

These are the

shlibs

files corresponding to all of the packages installed on the system,

and are maintained by the relevant package maintainers.

/etc/dpkg/shlibs.default

This file lists any shared libraries whose packages have failed to provide correct

shlibs

files. It was used when the

shlibs

setup was first introduced, but it is now normally

empty. It is maintained by the

dpkg

maintainer.

8.6.2 How to use

dpkg shlibdeps

and the

shlibs

files

Put a call to

dpkg shlibdeps

into your

debian/rules

file. If your package contains only

compiled binaries and libraries (but no scripts), you can use a command such as:

dpkg shlibdeps debian/tmp/usr/bin/* debian/tmp/usr/sbin/* \

debian/tmp/usr/lib/*

7

An example may help here. Let us say that the source package

foo

generates two binary packages,

libfoo2

and

foo runtime

. When building the binary packages, the two packages are created in the directories

debian

/libfoo2

and

debian/foo runtime

respectively. (

debian/tmp

could be used instead of one of these.) Since

libfoo2

provides the

libfoo

shared library, it will require a

shlibs

file, which will be installed in

debian

/libfoo2/DEBIAN/shlibs

, eventually to become

/var/lib/dpkg/info/libfoo2.shlibs

. Then when

dpkg shlibdeps

is run on the executable

debian/foo runtime/usr/bin/foo prog

, it will examine the

debian/libfoo2/DEBIAN/shlibs

file to determine whether

foo prog

's library dependencies are satisfied by

any of the libraries provided by

libfoo2

. For this reason,

dpkg shlibdeps

must only be run once all of the

individual binary packages'

shlibs

files have been installed into the build directory.