Provided by: dpkg-dev_1.14.20ubuntu6_all bug

NAME

       dpkg-shlibdeps - generate shared library substvar dependencies

SYNOPSIS

       dpkg-shlibdeps [options] executable|-eexecutable [options]

DESCRIPTION

       dpkg-shlibdeps  calculates  shared library dependencies for executables
       named in its arguments. The dependencies are added to the  substitution
       variables      file      debian/substvars     as     variable     names
       shlibs:dependencyfield where  dependencyfield  is  a  dependency  field
       name. Any other variables starting shlibs: are removed from the file.

       dpkg-shlibdeps  has  two  possible  sources  of information to generate
       dependency information. Either symbols files or shlibs files. For  each
       binary that dpkg-shlibdeps analyzes, it finds out the list of libraries
       that it’s linked with.  Then, for each library, it looks up either  the
       symbols  file,  or  the shlibs file (if the former doesn’t exist). Both
       files are supposed to be provided by the  library  package  and  should
       thus    be    available    as   /var/lib/dpkg/info/package.symbols   or
       /var/lib/dpkg/info/package.shlibs. The package name  is  identified  in
       two  steps:  find  the  library file on the system (looking in the same
       directories that ld.so would use), then use  dpkg  -S  library-file  to
       lookup the package providing the library.

   Symbols files
       Symbols files contain finer-grained dependency information by providing
       the minimum dependency for each symbol that the  library  exports.  The
       script  tries to find a symbols file associated to a library package in
       the following places (first match is used):

       debian/*/DEBIAN/symbols
              Shared  library  information  generated  by  the  current  build
              process that also invoked dpkg-shlibdeps.  They are generated by
              dpkg-gensymbols(1).  They are only used if the library is  found
              in  a  package’s build tree. The symbols file in that build tree
              takes precedence over symbols files from other binary  packages.

       /etc/dpkg/symbols/package.symbols.arch

       /etc/dpkg/symbols/package.symbols
              Per-system  overriding  shared  library  dependency information.
              arch is the architecture of  the  current  system  (obtained  by
              dpkg-architecture -qDEB_HOST_ARCH).

       admindir/info/package.symbols
              Package-provided  shared library dependency information.  Unless
              overridden, admindir is /var/lib/dpkg.

       While  scanning  the  symbols  used  by  all  binaries,  dpkg-shlibdeps
       remembers the (biggest) minimal version needed for each library. At the
       end of the process, it is able to write out the minimal dependency  for
       every  library used (provided that the information of the symbols files
       are accurate).

       As a safe-guard measure, a symbols file can  provide  a  Build-Depends-
       Package  meta-information  field  and  dpkg-shlibdeps  will extract the
       minimal version required by the corresponding  package  in  the  Build-
       Depends  field  and  use  this  version if it’s higher than the minimal
       version computed by scanning symbols.

   Shlibs files
       Shlibs files associate directly a  library  to  a  dependency  (without
       looking  at  the  symbols). It’s thus often stronger than really needed
       but very safe and easy to handle.

       The dependencies for a library are looked up  in  several  places.  The
       first file providing informations for the library of interest is used:

       debian/shlibs.local
              Package-local  overriding shared library dependency information.

       /etc/dpkg/shlibs.override
              Per-system overriding shared library dependency information.

       debian/*/DEBIAN/shlibs
              Shared  library  information  generated  by  the  current  build
              process that also invoked dpkg-shlibdeps.  They are only used if
              the library is found in a package’s build tree. The shlibs  file
              in that build tree takes precedence over shlibs files from other
              binary packages.

       admindir/info/package.shlibs
              Package-provided shared library dependency information.   Unless
              overridden, admindir is /var/lib/dpkg.

       /etc/dpkg/shlibs.default
              Per-system default shared library dependency information.

       The  extracted  dependencies are then directly used (except if they are
       filtered out because they have been  identified  as  duplicate,  or  as
       weaker than another dependency).

OPTIONS

       dpkg-shlibdeps  interprets  non-option  arguments  as executable names,
       just as if they’d been supplied as -eexecutable.

       -eexecutable
              Include  dependencies  appropriate  for  the  shared   libraries
              required by executable.

       -ddependencyfield
              Add  dependencies  to  be  added  to the control file dependency
              field dependencyfield.  (The dependencies  for  this  field  are
              placed in the variable shlibs:dependencyfield.)

              The  -ddependencyfield  option  takes effect for all executables
              after the option, until the next -ddependencyfield.  The default
              dependencyfield is Depends.

              If the same dependency entry (or set of alternatives) appears in
              more  than  one  of  the  recognised  dependency   field   names
              Pre-Depends,  Depends,  Recommends,  Enhances  or  Suggests then
              dpkg-shlibdeps will automatically remove the dependency from all
              fields   except   the   one   representing  the  most  important
              dependencies.

       -pvarnameprefix
              Start substitution  variables  with  varnameprefix:  instead  of
              shlibs:.  Likewise, any existing substitution variables starting
              with varnameprefix: (rather than shlibs:) are removed  from  the
              the substitution variables file.

       -O     Print  substitution variable settings to standard output, rather
              than  being   added   to   the   substitution   variables   file
              (debian/substvars by default).

       -ttype Prefer  shared  library  dependency  information  tagged for the
              given package type. If no tagged information is available, falls
              back to untagged information. The default package type is "deb".
              Shared library dependency information is tagged for a given type
              by  prefixing  it  with  the  name  of  the  type,  a colon, and
              whitespace.

       -Llocalshlibsfile
              Read  overriding  shared  library  dependency  information  from
              localshlibsfile instead of debian/shlibs.local.

       -Tsubstvarsfile
              Write  substitution  variables  in substvarsfile; the default is
              debian/substvars.

       -v     Enable verbose mode. Numerous messages are displayed to  explain
              what dpkg-shlibdeps does.

       -xpackage
              Exclude  the  package  from  the generated dependencies. This is
              useful to avoid self-dependencies for packages which provide ELF
              binaries  (executables  or  library  plugins)  using  a  library
              contained in the same package. This option can be used  multiple
              times to exclude several packages.

       -Spkgbuilddir
              Look  into pkgbuilddir first when trying to find a library. This
              is useful when the source package builds multiple flavors of the
              same  library and you want to ensure that you get the dependency
              from a given binary package. You can use  this  option  multiple
              times:  directories  will  be  tried  in  the  same order before
              directories of other binary packages.

       --ignore-missing-info
              Do not fail if dependency  information  can’t  be  found  for  a
              shared  library.   Usage  of  this  option  is  discouraged, all
              libraries should provide  dependency  information  (either  with
              shlibs  files,  or  with symbols files) even if they are not yet
              used by other packages.

       --warnings=value
              value is a bit field defining the set of warnings  that  can  be
              emitted  by dpkg-shlibdeps.  Bit 0 (value=1) enables the warning
              "symbol sym used by binary found in none of the libraries",  bit
              1  (value=2) enables the warning "dependency on library could be
              avoided"  and  bit  2  (value=4)  enables  the  warning  "binary
              shouldn’t  be linked with library".  The default value is 3: the
              first two warnings are active by default, the last one  is  not.
              Set value to 7 if you want all warnings to be active.

       --admindir=dir
              Change  the  location of the dpkg database. The default location
              is /var/lib/dpkg.

       -h, --help
              Show the usage message and exit.

       --version
              Show the version and exit.

WARNINGS

       Since dpkg-shlibdeps analyzes the set of symbols used by each binary of
       the  generated  package,  it is able to emit warnings in several cases.
       They inform you of things that can be improved in the package. In  most
       cases,  those  improvements  concern  the upstream sources directly. By
       order of decreasing importance, here are the various warnings that  you
       can encounter:

       symbol sym used by binary found in none of the libraries.
              The  indicated symbol has not been found in the libraries linked
              with the binary. The binary is most  likely  a  library  and  it
              needs  to  be linked with an additional library during the build
              process (option -llibrary of the linker).

       dependency on library could be avoided if binaries were  not  uselessly
       linked against it (they use none of its symbols).
              None of the binaries that are linked with library use any of the
              symbols provided by the library. By fixing all the binaries, you
              would avoid the dependency associated to  this  library  (unless
              the same dependency is also generated by another library that is
              really used).

       binary shouldnt be linked with library (it uses none of its  symbols).
              The binary is linked to a library that it doesn’t need. It’s not
              a problem but some small performance improvements in binary load
              time can be obtained by not linking this library to this binary.
              This  warning  checks the same information than the previous one
              but does it for each binary instead of doing the check  globally
              on all binaries analyzed.

ERRORS

       dpkg-shlibdeps  will  fail  if it can’t find a public library used by a
       binary or if this library  has  no  associated  dependency  information
       (either shlibs file or symbols file). A public library has a SONAME and
       is versioned (libsomething.so.X). A private  library  (like  a  plugin)
       should not have a SONAME and doesn’t need to be versioned.

       couldnt  find  library  library-soname  needed by binary (its RPATH isrpath)
              The   binary   uses   a   library   called   library-soname  but
              dpkg-shlibdeps  has   been   unable   to   find   the   library.
              dpkg-shlibdeps  creates  a  list  of  directories  to  check  as
              following: directories  listed  in  the  RPATH  of  the  binary,
              directories listed in /etc/ld.so.conf, directories listed in the
              LD_LIBRARY_PATH  environment  variable,  and   standard   public
              directories   (/lib,   /usr/lib,   /lib32,  /usr/lib32,  /lib64,
              /usr/lib64). Then it checks those directories in  the  package’s
              build tree of the binary being analyzed, in the packages’s build
              trees indicated  with  the  -S  command-line  option,  in  other
              packages’s   build   trees  that  contains  a  DEBIAN/shlibs  or
              DEBIAN/symbols file and finally in the root directory.   If  the
              library  is  not found in any of those directories, then you get
              this error.

              If the library not found is in a private directory of  the  same
              package,  then you want to add the directory to LD_LIBRARY_PATH.
              If it’s in another binary package being built, you want to  make
              sure  that  the  shlibs/symbols  file of this package is already
              created  and  that  LD_LIBRARY_PATH  contains  the   appropriate
              directory if it also is in a private directory.

       no dependency information found for library-file (used by binary).
              The library needed by binary has been found by dpkg-shlibdeps in
              library-file but dpkg-shlibdeps has  been  unable  to  find  any
              dependency  information  for  that  library.  To  find  out  the
              dependency, it has tried to map the library to a Debian  package
              with  the  help  of  dpkg  -S library-file.  Then it checked the
              corresponding shlibs and symbols files  in  /var/lib/dpkg/info/,
              and in the various package’s build trees (debian/*/DEBIAN/).

              This failure can be caused by a bad or missing shlibs or symbols
              file in the package of the library. It might also happen if  the
              library  is  built  within  the  same  source package and if the
              shlibs files has not yet been created (in which  case  you  must
              fix   debian/rules   to   create   the   shlibs  before  calling
              dpkg-shlibdeps). Bad RPATH can also lead to  the  library  being
              found      under      a     non-canonical     name     (example:
              /usr/lib/gcc/i486-linux-gnu/4.2.3/../../../../lib/libssl.so.9.8
              instead  of  /usr/lib/libssl.so.0.9.8)  that’s not associated to
              any package, dpkg-shlibdeps tries to work around this by  trying
              to fallback on a canonical name (using realpath(3)) but it might
              not always work. It’s always best to clean up the RPATH  of  the
              binary to avoid problems.

              Calling  dpkg-shlibdeps  in  verbose mode (-v) will provide much
              more information about where it tried  to  find  the  dependency
              information.  This  might  be useful if you don’t understand why
              it’s giving you this error.

SEE ALSO

       deb-shlibs(5), deb-symbols(5), dpkg-gensymbols(1).

AUTHORS

       Copyright (C) 1995-1996 Ian Jackson
       Copyright (C) 2000 Wichert Akkerman
       Copyright (C) 2006 Frank Lichtenheld
       Copyright (C) 2007-2008 Raphaël Hertzog

       This is free software; see the GNU General Public Licence version 2  or
       later for copying conditions. There is NO WARRANTY.