void DisplayChangelog(CacheFile& Cache, pkgCache::VerIterator V) {

   pkgCache::VerFileIterator Vf = V.FileList();

   for (; Vf.end() == false; Vf++)

     if ((Vf.File()->Flags & pkgCache::Flag::NotSource) == 0)

       break;

   if (Vf.end() == true)

     Vf = V.FileList();

   pkgRecords Recs(*Cache);

   pkgRecords::Parser &P = Recs.Lookup(Vf);

   std::cout << "Changelog for " << P.Name() << ":\n";

   std::cout << P.Changelog() << "\n";

}

bool DoChangelog(CommandLine &CmdL) {

   // Implementation is very similar to apt-cache show

   CacheFile Cache(devnull, false /* not WithLock */);

   if (Cache.Open() == false)

     return false;

   if (CmdL.FileSize() <= 1)

     return _error->Error(_("Must specify at least one package to get changelog for"));

   pkgDepCache::Policy Plcy;

   unsigned int found = 0;

   for (const char **I = CmdL.FileList + 1; *I != 0; ++I) {

    pkgCache::PkgIterator Pkg = Cache->FindPkg(*I);

    if (Pkg.end() == true) {

      _error->Warning(_("Unable to locate package %s"), *I);

      continue;

    }

    ++found;

    // If it's a virtual package, require user to select

    if (Pkg.VersionList().end() == true and Pkg->ProvidesList != 0) {

      ioprintf(cout, _("Package %s is a virtual package provided by:\n"),

               Pkg.Name());

      for (pkgCache::PrvIterator Prv = Pkg.ProvidesList(); Prv.end() == false;

           Prv++) {

        pkgCache::VerIterator V = Plcy.GetCandidateVer(Prv.OwnerPkg());

        if (V.end() == true)

          continue;

        if (V != Prv.OwnerVer())

          continue;

        cout << "  " << Prv.OwnerPkg().Name() << " " << V.VerStr() << endl;

      }

      _error->Error(

          _("Package %s is a virtual package with multiple providers."),

          Pkg.Name());

      return false;

    }

   // Find the proper version to use.

   pkgCache::VerIterator V = Plcy.GetCandidateVer(Pkg);

   if (V.end() == true || V.FileList().end() == true)

     continue;

   DisplayChangelog(Cache, V);

  }

  if (found > 0)

    return true;

  return _error->Error(_("No packages found"));

}

      "   changelog - Display the changelog for the given package\n"

				   {"changelog",&DoChangelog},