Dynamic libraries by default and GHC 7.8

Ian Lynagh ian at well-typed.com
Tue Nov 27 18:00:17 CET 2012

On Tue, Nov 27, 2012 at 10:22:12AM -0500, Stephen Paul Weber wrote:
> Somebody claiming to be Ian Lynagh wrote:
> >GHC HEAD now has support for using dynamic libraries by default (and in
> >particular, using dynamic libraries and the system linker in GHCi) for a
> >number of platforms.
> >
> >The various issues are described in a wiki page here:
> >   http://hackage.haskell.org/trac/ghc/wiki/DynamicByDefault
> IIRC, one of the problems with dynamic linking in GHC is that when
> the GHC version is different, the ABI can often be different enough
> to making such shared libraries incompatible with each other /
> binaries made on different GHCs.  This makes distribution a
> potential nightmare (where you have to package all the *.so files
> and send them along with your binary, which is essentially the same
> as static linking, but more pain).  Is this no longer the case, or
> am I completely misremembering this?

That is still the case. However, if you want to distribute binaries then
you will still be able to build with -static if you don't want to have
ot bundle a load of DLLs. It's only the default that will change.

> Also, you say "for a number of platforms" and that wiki page says
> "Currently, we don't know how to do dynamic-by-default on Windows in
> a satisfactory way."  So I assume Windows is not one of the
> platforms that would be seeing this change?

We would love for Windows to be one of the platforms, but currently we
can't do it on Windows. So unless that changes, Windows will not be one
of the platforms, correct.


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