[racket] copy-shared-files and different platforms

At Tue, 26 Aug 2014 16:48:24 +0200, Jens Axel Søgaard wrote:
> 2014-08-26 1:46 GMT+02:00 Matthew Flatt <mflatt at cs.utah.edu>:
> > At Mon, 25 Aug 2014 18:50:24 +0200, Jens Axel Søgaard wrote:
> >> > The "@loader_path" references mean that the shared libraries as
> >> > currently compiled work only when installed in the same scope as the
> >> > `racket/draw` libraries. Offhand, I don't have a good idea for solving
> >> > this problem. (FWIW, Windows installations won't have this problem.)
> >
> > I've changed `raco setup` to replace "@loader_path" in installed Mach-O
> > files with an absolute path as needed.
> 
> Sounds great.
> 
> I have a similar problem on Windows 7 Enterprise SP1.
> 
> The dynamic library is copied into the result of (find-user-lib-dir)
> namely c:\Users\js\AppData\Roaming\Racket\6.1\lib
> 
> The odd thing is that (ffi-lib "libpoppler-glib" '("8")) looks
> for "libpoppler-glib.dll.8" instead of "libpoppler-glib-8.dll".
> 
> Should I just rename the file or is it a bug?

I think the way that version numbers are currently added to Windows DLL
names is probably not useful, and I will look into adjusting that.
Meanwhile, you could use `ffi-lib` on a different library name for
Windows, which is how `racket/draw`, etc., currently work.

Another detail for Windows is that you need to explicitly load a DLL X
is that referenced by a DLL Y before loading Y. That's the flip side of
not having to worry about something like "@loader_path": instead of a
static reference to another library embedded in the DLL, the "path" is
determined dynamically by loading a shared library before it is needed.


That load-before-reference issue is partly why you see a list of DLLs
at

https://github.com/plt/racket/blob/master/pkgs/draw-pkgs/draw-lib/racket/draw/unsafe/cairo-lib.rkt

Another reason for the list of libraries there (and why it shows up for
Mac OS X, too) is to ensure that shared libraries are pulled along for
stand-alone executables. The `define-runtime-lib` macro expands to
`define-runtime-path-list` as well as `ffi-lib`.