[Haskell-cafe] using a win32 dll (Happy too soon)

[Brandon Allbery]

On Wed, May 29, 2013 at 9:40 AM, Kees Bleijenberg <
k.bleijenberg at lijbrandt.nl> wrote:

> If I compile with ghc --make testGlasPng.hs –lglasPng I get: ….\ld.exe:
> cannot find –lglasPng. Collect 2: ld returned 1 exit status.
>
> **
>
> Ld can’t find lglasPng (with the l in front, does it trim the l?). Why?
> Okay I try
>

It's reproducing the thing passed to it, rather than outputting both the
dll and implib versions that it actually looks for. Same happens on
unixlikes where it's looking for a .so/.dylib/whatever or a .a.

****
>
> ghc --make testGlasPng.hs –L<path to glasPng.dll> I get:
>

Not quite right; -L identifies a *directory* to search, then you must
specify the actual filename afterward.


> ****
>
> testGlasPng.o: fake: (.text + 0x82) :undefined reference to
> ‘getPngVersion at 0’. I think it has found  the
>

This just means it can't find the symbol; it does not mean it necessarily
found the DLL.


> I run ghc on a 64 bits computer. The dll is 32 bits. Is that the problem?
>

That can certainly be a problem, yes, and is likely why it wasn't found
with the first one. But it's not so much what kind of machine you are on,
as what kind of ghc you are using: a 64-bit ghc cannot link 32-bit
libraries, and vice versa. But a 32-bit ghc and toolchain will work fine on
a 64-bit system, aside from not linking 64-bit DLLs.

-- 
brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
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