Re: Linking libraries

From:
James Kanze <james.kanze@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Mon, 5 Jul 2010 05:32:10 -0700 (PDT)
Message-ID:
<88a02d9a-bf0b-4a4f-9e94-bbf7e22a6e98@r27g2000yqb.googlegroups.com>
On Jul 4, 9:40 pm, Ian Collins <ian-n...@hotmail.com> wrote:

On 07/ 4/10 11:59 PM, James Kanze wrote:

On Jul 2, 11:47 pm, Ian Collins<ian-n...@hotmail.com> wrote:

On 07/ 3/10 10:31 AM, Paavo Helde wrote:

Agreed. DLL sharing is useful only if the DLL is really
stable. In Windows world this would be kernel32.dll and
such. On Linux the C runtime also qualifies, but not in
Windows as there are so many uncompatible versions.


While true, that's a bit too narrow in scope. On my platform
of choice (Solaris), static libraries are largely historical.
On most if not all Unix derived systems, shared libraries are
the way to go.


For the system libraries (e.g. libc.so); I don't think that
Sun/Oracle even deliver statically linkable versions any more.
In some ways, the same holds for Windows. The difference is
that Windows does provide the statically linkable versions, and
that not all of the dynamically linkable versions are bundled
with the OS, so you sometimes have to ship them as well.

For anything above the system level (including the C++ standard
library), I'd go with static linking, unless I specifically
needed some particular behavior of dynamic linking (choosing the
version of the library at runtime, for example).


Interesting, I prefer dynamic linking. Mainly because there
are fewer link order dependencies. I also tend to have
several applications based on common libraries running on any
given system.


I've never found link order dependencies a problem; if you've
a clean design, there should be no cycles, and the order of
dependencies is well established. There may be issues with
third party libraries, if they don't document the dependencies,
but that only has to be solved once.

I don't know about windows, but a lot of my debug tools
(memory access checking, profiling) can be selectively enabled
on a per-module basis.


Debugging is one possible advantage of dynamic linking. Most
systems do provide some sort of hooking for function calls
accross dynamic object interfaces. But it doesn't seem worth
the extra cost in deployment.

--
James Kanze

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