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What is the purpose of _c.h files?

asked 2013-06-03 02:24:08 -0500

mtngardener gravatar image

I am running into issues with my OpenCV install. Trying to run various tutorials I am getting errors during compilation where constants aren't defined. When I search for the definitions I find that they are in files that end with _c.h. These files don't seem to be included anywhere. I don't see how to build without including them, but for some of them, when I add them it just makes the problems worse (for example, including highgui_c.h fixes a problem, but including core_c.h causes a chain of additional requirements that seems insoluble).

What is the idea behind _c.h files? When should they be included? How should they be included?

I am running with VC2012 on Windows 7. I am able to build and run the example code. I am currently trying to get the Camera Calibration tutorial code to run:

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btw, please add the opencv version to your post

berak gravatar imageberak ( 2013-06-03 03:56:48 -0500 )edit

It is version 2.4.9, I'd guess, since my lib files end with "249.lib".

mtngardener gravatar imagemtngardener ( 2013-06-05 00:03:43 -0500 )edit

oh, jikes, that's quite a different setup

berak gravatar imageberak ( 2013-06-05 00:55:55 -0500 )edit

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answered 2013-06-03 03:55:49 -0500

berak gravatar image

updated 2013-06-03 04:01:27 -0500

usually they contain the old c-api functionality.

you should never need to include them directly

to access the c-api, you'd go like:

#include <opencv/highgui.h>

for the c++ (2.x) api:

#include <opencv2/highgui/highgui.hpp>

don't resolve to hacking, you won't get far that way.

there must be something wrong in your vcproj file, or the install.

there's 2 ways to get the headers right:

  • easy(using the prebuilt stuff:

    point your "Additional Include Dirs" at opencv/build/include

    (it should just work , if that folder contains all the nessecary headers).

    note that if you build your own libs, cmake might install the headers in a "build/install/include" folder, check with cmake-gui, where things go!

  • hard(but safe):

    point your "Additional Include Dirs" at opencv/include, additionally for each module, add it's module path, like opencv/modules/highgui/include opencv/modules/core/include ,...

    more work, but this way, you don't depend on install things. (that's what cmake does, when you ask it to generate your own project depending on opencv)

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So I should be pointing my VS2012 project's "Additional Include Dirs" to "install/include/opencv2"? If I do that, then do I need any of the #include "opencv2/foo" statements?

mtngardener gravatar imagemtngardener ( 2013-06-05 00:12:48 -0500 )edit

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Asked: 2013-06-03 02:24:08 -0500

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Last updated: Jun 03 '13