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On a mac, I've done brew install freetds, which gives me a file libtdsodbc.so. Now I try to link to that by putting the path to it in extra-lib-dirs in my .cabal, but I get 

* Missing (or bad) C library: tdsodbc
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 the
library file does exist, it may contain errors that are caught by the C
compiler at the preprocessing stage. In this case you can re-run configure
with the verbosity flag -v3 to see the error messages.

Doing stack build --verbose shows me the command that fails was cabal configure, so I run that again with -v3 appended, which tells me:

/usr/bin/gcc -fno-stack-protector /var/folders/bq/4xy9knvx413dwltf9c6ngvvm0000gt/T/29185-4.c -o /var/folders/bq/4xy9knvx413dwltf9c6ngvvm
0000gt/T/29185-5 '-D__GLASGOW_HASKELL__=804' '-Ddarwin_BUILD_OS=1' '-Dx86_64_BUILD_ARCH=1' '-Ddarwin_HOST_OS=1' '-Dx86_64_HOST_ARCH=1' -
I.stack-work/dist/x86_64-osx/Cabal-2.2.0.1/build/autogen -I. -I/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/base-4
.11.1.0/include -I/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/integer-gmp-1.0.2.0/include -I/Users/unhammer/.stac
k/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/include -ltdsodbc -L/Users/unhammer/src/tds/lib -L/Users/unhammer/.stack/programs/x86_64-o
sx/ghc-8.4.3/lib/ghc-8.4.3/base-4.11.1.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/integer-gmp-1.0.2.0 -L/Use
rs/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/ghc-prim-0.5.2.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/l
ib/ghc-8.4.3/rts                                                                                                   
/usr/bin/gcc returned ExitFailure 1 with error message:
ld: can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB) file
'/Users/unhammer/src/tds/lib/libtdsodbc.so' for architecture x86_64                                                                     
clang: error: linker command failed with exit code 1 (use -v to see                                                                     
invocation)                                                                                                                             
/usr/bin/gcc -fno-stack-protector /var/folders/bq/4xy9knvx413dwltf9c6ngvvm0000gt/T/29185-6.c -o /var/folders/bq/4xy9knvx413dwltf9c6ngvvm
0000gt/T/29185-7 -ltdsodbc -L/Users/unhammer/src/tds/lib -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/base-4.11.1.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/integer-gmp-1.0.2.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/ghc-prim-0.5.2.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/rts             
/usr/bin/gcc returned ExitFailure 254 with error message:
ld: can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB) file
'/Users/unhammer/src/tds/lib/libtdsodbc.so' for architecture x86_64
clang: error: unable to execute command: Segmentation fault: 11
clang: error: linker command failed due to signal (use -v to see invocation)
/usr/bin/gcc -fno-stack-protector /var/folders/bq/4xy9knvx413dwltf9c6ngvvm0000gt/T/29185-8.c -o /var/folders/bq/4xy9knvx413dwltf9c6ngvvm
0000gt/T/29185-9 -ltdsodbc -L/Users/unhammer/src/tds/lib -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/base-4.11.
1.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/integer-gmp-1.0.2.0 -L/Users/unhammer/.stack/programs/x86_64-os
x/ghc-8.4.3/lib/ghc-8.4.3/ghc-prim-0.5.2.0 -L/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/rts
/usr/bin/gcc returned ExitFailure 1 with error message:
ld: can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB) file
'/Users/unhammer/src/tds/lib/libtdsodbc.so' for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see
invocation)
/usr/bin/gcc -fno-stack-protector /var/folders/bq/4xy9knvx413dwltf9c6ngvvm0000gt/T/29185-10.c -o /var/folders/bq/4xy9knvx413dwltf9c6ngvv
m0000gt/T/29185-11 -c '-D__GLASGOW_HASKELL__=804' '-Ddarwin_BUILD_OS=1' '-Dx86_64_BUILD_ARCH=1' '-Ddarwin_HOST_OS=1' '-Dx86_64_HOST_ARCH
=1' -I.stack-work/dist/x86_64-osx/Cabal-2.2.0.1/build/autogen -I. -I/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/b
ase-4.11.1.0/include -I/Users/unhammer/.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/integer-gmp-1.0.2.0/include -I/Users/unhammer/
.stack/programs/x86_64-osx/ghc-8.4.3/lib/ghc-8.4.3/include

Why can't ld link to MH_BUNDLE? Can cabal only link to dylib's on mac, or do I need some special options?

EDIT: Solved by instead linking to the dylib's that the .so links to.

unhammer
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  • I found the top answer very confusing (shared libraries are distinguished from dynamically loaded modules but both can be dynamically loaded and shared are called dylib/dynamiclib?). But it does say `It is not possible to link against bundles as if they were shared libraries. However, it is possible that a bundle is linked against real shared libraries; those will be loaded automatically when the bundle is loaded.` Can Cabal do that? – unhammer Mar 07 '19 at 08:07
  • In our case, it seems like we can work around it by linking to the libs that the .so links to, so I'll close this as dupe. (I still have some unanswered questions, but now my only motivation to have them answered is curiosity.) – unhammer Mar 07 '19 at 10:12

0 Answers0