Hans wrote: > Hi Folks, > > I would like to rebuild or repack an old application, which needs a library, > which is no more used in debian. Due to this orphaned lib, this package can > no > more installed. > > The lib, which is responsible is "libqt3-mt". I believe, there might be a > successor for this special lib. > > For my understanding: > > 1. If there is a successor for a special lib, does it then contain all > routines of the older lib? Exactly: Can a lib just exchanged againts a newer > one?
Not necessarily. This is sometimes true, especially when the versions are very close together. 3.09 is likely to be very similar to 3.10, but not very much like 5.1. > 2. If I want to rebuild the binary just because of the newer lib, can this > just be done, by exchanging the entry of the old lib against a newer one? Sometimes, but not always. For example, if the new library changed all calls from DrawRectangle to DrawPolygon(rectangle), it won't work. > 3. If I do not want to rebuild the sources, just repack the package, so that > its dependencies fits again in debians repo, will it work, when just > exchanging the lib in the "control" file in the package? No. A program exists in two forms: source code, which humans can read and write, and machine code, which is executed by the computer. (I am oversimplifying this for the sake of brevity.) To take in source code and produce machine code can be done in one of two ways: - an interpreted language reads the source code at the time you run the program -- really, you are running the interpreter and feeding it the source code files -- and produces machine code that it also runs at that time. - a compiled language reads the source code when the compiler is run, and produces machine code in a new file which can be run without the compiler. An interpreted library is a set of useful bits of code that are called in by the interpreter when it is directed to do so by the source code. "Please read this library and let me use the DrawRectangle function." The source code needs to specify exactly what library it wants to use, so changing out the library will require at least a small change to update that. A compiled library is a set of useful bits of code that are called in by the compiler when it is directed to do by the source code -- and it is incorporated into the eventual binary directly (static linking) or a reference to the right bytes in an external file is included into the binary (dynamic linking). -dsr-
