Re: [Haskell-cafe] Trying desperately to make a c library binding on Windows - solved!

18 Mar 2016


      Thanks for this information, didn't know it, I will begin to work like 
this too.
Beeing the first time when I try to link to external C libs I guess 
there will be more to learn anyway :-)
Nicu

Am 18.03.2016 um 22:40 schrieb Michał Antkiewicz:
...
I always use the MSYS/MinGW provided with stack. It has pacman and
everything so there's no need to have a custom installation of MSYS
(which I used to do before).
You can start the shell using the script
mingw64_shell.bat
located in
C:\Users\<user name>\AppData\Local\Programs\stack\x86_64-windows\msys2-20150512
Glad it worked out.
--
Michał
On Fri, Mar 18, 2016 at 4:53 PM, Nicu Ionita  wrote:
...
This was really dumb.
My MinGW was just a 32 bit installation, but the stack is version 1.0.4.2
x86_64, so (I guess) the default arch of the project is x86_64.
The extra-lib-dirs & extra-libraries were ok, but trhu the filters of stack
I could not see that ld ignored the incompatible libraries. So it looked
(even with --verbose) like the libraries were not found, when in fact they
were just incompatible.
Now at least this is clarified.
Sorry for the noise.
Nicu
Am 18.03.2016 um 00:05 schrieb Nicu Ionita:
...
What I don't understand is why the stack message sounds:
If the library is already installed but in a non-standard location then
you can use the flags
--extra-include-dirs= and --extra-lib-dirs= to specify where it is.
Why would be an include directory necessary, if I only miss the library? I
understand that the includes are needed to compile the (generated) C
sources, but why needed to link? Or is maybe just a typo in the stack
message?
Nicu
Am 17.03.2016 um 23:50 schrieb Nicu Ionita:
...
Am 17.03.2016 um 23:24 schrieb Theodore Lief Gannon:
...
...
I am on Win 7, using stack (configured for lts-4.2) under MinGW.
Stack itself provides MSYS2/MinGW during builds on Windows. Do you mean
you have an independent MinGW shell that you're opening, and then running
stack from there?
Yes, I work under the git bash (git for Windows comes with an own msys).
...
If so, assuming you're not already using this flag, try:
stack build --skip-msys
Just tried that now, same result.
...
This tells stack that it's already running inside a unix-style shell,
and shouldn't assert its related path overrides.
Beyond that, it would help to have more information about exactly where
everything is and how it's being built/invoked/etc.
Project is under:
J:\Projects\BaseOh
Library is under:
J:\BO\lib
and is called:  libbayesopt.a
(under bash they are called /j/Projects/BaseOh and /j/BO/lib, needless to
say I tried those too, but they are not found, as the programs know only
Windows style paths).
...
stack build
or even:
stack build --extra-lib-dirs=j:\\BO\\lib
But in both cases, if the line "extra-libraries: bayesopt" is present in
So beeing under the git bash in the project directory, I type:
the cabal file, then configure does not work (message below).
Inbetween I upgraded stack (now is version 1.0.4.2 x86_64). When I try to
build, I get the message:
Continuing despite missing tool: msys2
after which the build continues and brings exactly the same failures.
...
On Thu, Mar 17, 2016 at 2:19 PM, Nicu Ionita mailto:nicu.ionita@acons.at> wrote:
Hi all,
I am really stuck with my try to make a Haskell binding for the
     library bayesopt on Windows.
     In theory it looks all simple, just put some lines in the cabal
     configuration file:
...
     extra-lib-dirs:      /path/to/the/lib    -- contains the file
     libbayesopt.a
     extra-libraries:    bayesopt
     ...
But whatever I tried, I can't step over the configuration phase,
     coz I get (I'm compiling with stack):
Configuring BaseOh-0.1.0.0...
     setup-Simple-Cabal-1.22.5.0-x86_64-windows-ghc-7.10.3.exe: Missing
     dependency
     on a foreign library:
     * Missing C library: /j/BO/lib/libbayesopt.a
     This problem can usually be solved by installing the system
     package that
     provides this library (you may need the "-dev" version). If the
     library is
     already installed but in a non-standard location then you can use
     the flags
     --extra-include-dirs= and --extra-lib-dirs= to specify where it is.
If I comment those lines out, then the configure phase succeeds,
     the library is compiled (i.e. my binding library), but a test
     executable in the same project does of course not compile, as
     symbols are missing:
...
     In-place registering BaseOh-0.1.0.0...
     Preprocessing executable 'test' for BaseOh-0.1.0.0...
     [1 of 2] Compiling Optimisation.Stochastic.BayesOpt (
     src\Optimisation\Stochasti
     c\BayesOpt.hs,
.stack-work\dist\x86_64-windows\Cabal-1.22.5.0\build\test\test-tm
     p\Optimisation\Stochastic\BayesOpt.o )
     ghc.exe: unable to load package `BaseOh-0.1.0.0'
     ghc.exe:
J:\Projects\BaseOh\.stack-work\dist\x86_64-windows\Cabal-1.22.5.0\build
     \HSBaseOh-0.1.0.0-GdNObdePATgDIW1I2OVwEc.o: unknown symbol
     `initialize_parameter
     s_to_default'
--  While building package BaseOh-0.1.0.0 using:
     ...
Does somebody have some idea, what is going on?
I am on Win 7, using stack (configured for lts-4.2) under MinGW.
     (I'm using inline-c to make the bindings, and the same trick for
     include - include-dirs: ... - worked fine.)
Thanks, and sorry for the longer email.
     Nicu
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