#9010: TemplateHaskell leads to an "unknown symbol" error -------------------------------------+------------------------------------- Reporter: Feuerbach | Owner: Type: bug | Status: infoneeded Priority: high | Milestone: Component: Compiler | Version: 7.10.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by rwbarton): For example, when I build `play` with `cabal install --ghc-option=-v`, I get a bunch of output including the lines {{{ ... Loading package primitive-0.6.1.0 ... linking ... done. Loading package vector-0.11.0.0 ... linking ... done. Loading package lens-4.13 ... linking ... done. *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/tmp/th-unknown- symbol-test/.cabal-sandbox/lib/x86_64-linux- ghc-7.10.1/hsope_3XpfF7vOgxLEUT7DVeoPSc --print-file-name libopencv_calib3d.so *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/tmp/th-unknown- symbol-test/.cabal-sandbox/lib/x86_64-linux- ghc-7.10.1/hsope_3XpfF7vOgxLEUT7DVeoPSc --print-file-name libopencv_contrib.so ... *** gcc: /usr/bin/gcc -fno-stack-protector -DTABLES_NEXT_TO_CODE -L/tmp/th-unknown- symbol-test/.cabal-sandbox/lib/x86_64-linux- ghc-7.10.1/hsope_3XpfF7vOgxLEUT7DVeoPSc --print-file-name libopencv_videostab.so Loading package hs-opencv-binding-0.0.0 ... linking ... done. }}} That means GHC loaded the dynamic OpenCV libraries with `dlopen()`. In your case, it is apparently not doing that. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/9010#comment:14 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler