Am 19.12.2011, 20:43 Uhr, schrieb Jacob Carlborg <d...@me.com>:
It could be useful for a package manager. Theoretically all installed
packages could share the same dynamic library. But I would guess the the
packages would depend on different versions of the library and the
package manager would end up installing a whole bunch of different
versions of the Phobos and druntime.
No! Let's please try to get closer to something that works with package
managers than the situation on Windows.
On Windows I see few applications that install libraries separately,
unless they started on Linux or the libraries are established like
DirectX. In the past DLLs from newly installed programs used to overwrite
existing DLLs. IIRC the DLLs were then checked for their versions by
installers, so they are never downgraded, but that still broke some
applications with library updates that changed the API. Starting with
Vista, there is the winsxs difrectory that - as I understand it - keeps a
copy of every version of every dll associated to the programs that
installed/use them.
Package managers are close to my ideal world:
- different API versions (major revisions) can be installed in parallel
- applications link to the API version they were designed for
- bug fixes replace the old DLL for the whole system, all applications
benefit
- RAM is shared between applications that use the same DLL
I'd think it would be bad to make cuts here. If you cannot even imagine an
operating system with 1000 little apps like type/cat, cp/copy, sed etc...
written in D, because they would all link statically against the runtime
and cause major bloat, then that is turning off another few % of C users
and purists. You don't drive an off-road car, because you go off-roads so
often, but because you could imagine it. (Please buy small cars for city
use.)
Linking against different library versions goes in practice like this:
There is at least one version installed, maybe libphobos2.so.1.057. The 1
would be a major revision (one where hard deprecations occur), then there
is a link named libphobos2.so.1 to that file, that all applications using
API version 1 link against. So the actual file can be updated to
libphobos2.so.1.058 without recompiles or breakage.
