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amnipar edited this page Mar 30, 2012 · 7 revisions

Problems Building?

Lexical Error '#'

CV/Image.chs.h:1: (column 1) [ERROR]  >>> Lexical error !
The character '#' does not fit here.

This is probably due to misconfiguration of your system. Solution: Build using LANG=C, for example:

> LANG=C cabal-dev install

Note: On some environments it has been necessary to set LANGUAGE=C also.

Missing C2HS

To install CV you also need to install c2hs, since cabal doesn't (I think) track installation of executables. Simple cabal install c2hs should be enough. Also, make sure that c2hs is in the path.


dist/build/CV/Video.chs.h:24: (column 32) [ERROR]  >>> Unknown identifier!
Cannot find a definition for `CV_CAP_PROP_WHITE_BALANCE` in the header file.

This is due to using opencv library version greater than 2.2. To build with 2.3 or newer, supply the flag -fopencv23 to cabal. For example:


cabal-dev install -fopencv23

CV.Bindings.Matrix filename doesn't match module name

    File name does not match module name:
    Saw: `Main'
    Expected: `CV.Bindings.Matrix'

This problem is due installing bindings-dsl with cabal-dev. Or atleast it can be fixed by a local install of bindings-dsl.

Solution: do cabal install bindings-dsl instead of cabal-dev install bindings-dsl

Missing shared libraries when running compiled programs

error while loading shared libraries: 
      libopencv_**.so.2.3: cannot open shared object file: 
      No such file or directory

This happens when opencv is installed outside your library path. Solution:

  1. Find out the location of libopencv* shared objects. By default they are installed in /usr/local/lib
  2. Add this directory to /etc/
  3. Run ldconfig
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