[fpc-devel] FPC dynamic libraries

[Mattias Gaertner]

On Wed, 7 Feb 2007 21:56:54 +0100
Jonas Maebe <jonas.maebe at elis.ugent.be> wrote:

> 
> On 07 Feb 2007, at 21:45, Mattias Gaertner wrote:
> 
> >> In principle you should be able to do it with "make shared" in the
> >> respective directories. But I would strongly recommend against
> >> doing that, since the interface is by no means stable and
> >> consequently programs compiled against both newer and older
> >> rtl/fcl's are very likely to break if they use a different rtl
> >> (and possibly fcl, since the fcl also uses rtl functionality).
> >
> > That's a general problem with libs, isn't it?
> 
> Yes, but especially with libraries where the developers have not  
> committed to maintaining backwards compatibility with a particular  
> interface and which are often changed in an ad hoc fashion. The main  
> problem is probably that we mix both general and compiler-specific  
> stuff in the system unit. It should probably be split into something  
> like gcc's libgcc.a (which contains compiler-specific helper  
> routines) and the system's libc dynamic library (system and generic
> C language support) before the rtl is ever distributed as a shared  
> library.
> 
> > We need a version system.
> 
> That's not something "we" need, but which most OS'es need (and don't  
> provide, except for hacks like symlinks or different filenames).  
> Moreover, it doesn't really solve much unless you like having 20  
> different versions of the same shared library on your system (which  
> would more or less defeat the purpose of saving space, although it  
> could still save memory if more than one FPC program is running at  
> the same time).
> 
> What problem do you want to solve with having a shared library? 

Plugins. For example installing a design time package.
Contrary to normal apps an IDE has the advantage to recompile
if needed. So Lazarus has only a subset of the normal dyn lib problems.
But I know, that as soon as the IDE can load packages as dynamic libs,
programmers will use dyn libs for their apps too and probably use
them as shared libs. And then FPC+Lazarus bug tracker will get new
trouble. So although I only want plugins, I ask about libs in
general.


> The  
> complaint that Lazarus programs are too large? Personally, I think  
> switching to shared libraries will at this time introduce a lot more  
> complaints that it will solve (and not because of a lack of a  
> versioning system, but simply because the interface isn't anywhere  
> near stable enough imho).


Mattias