On Wed, 2010-06-30 at 18:37 +0200, N J wrote: > Hi, > > I have a question about how to find a function in the opencv library. > > I tried this: > > (require :cffi) > > ;; load shared libs > (cffi:load-foreign-library "libcv.so") > (cffi:load-foreign-library "libhighgui.so") > > ;; define the function call CvCapture* capture = cvCaptureFromCAM( -1 ); > (cffi:defctype cvcapture :pointer) > (cffi:defcfun "cvCaptureFromCAM" > cvcapture > (type :int)) > > But I get: > STYLE-WARNING: Undefined alien: "cvCaptureFromCAM" > > Which means that "cffi" cannot find the name in the shared object file. > > My shared object file looks like this: > > nm /usr/lib64/libhighgui.so | grep -i cvcapturefromcam > 000000000023d180 b _ZZL21icvCaptureFromCAM_V4LiE9autoindex > > nm /usr/lib64/libhighgui.so | grep -i cvcapturecam > 0000000000021760 t _ZL15icvCloseCAM_V4LP16CvCaptureCAM_V4L > 0000000000021fa0 t _ZL15icvSetVideoSizeP16CvCaptureCAM_V4Lii > 00000000000225f0 t _ZL19icvGrabFrameCAM_V4LP16CvCaptureCAM_V4L > 00000000000216a0 t _ZL33v4l2_scan_controls_enumerate_menuP16CvCaptureCAM_V4L > 0000000000021940 T _ZN20CvCaptureCAM_V4L_CPP11getPropertyEi > 00000000000221c0 T _ZN20CvCaptureCAM_V4L_CPP11setPropertyEid > 0000000000021d60 T _ZN20CvCaptureCAM_V4L_CPP13retrieveFrameEi > 0000000000022a10 T _ZN20CvCaptureCAM_V4L_CPP4openEi > 0000000000021880 T _ZN20CvCaptureCAM_V4L_CPP5closeEv > 00000000000229f0 T _ZN20CvCaptureCAM_V4L_CPP9grabFrameEv > 00000000000218b0 W _ZN20CvCaptureCAM_V4L_CPPD0Ev > 0000000000021900 W _ZN20CvCaptureCAM_V4L_CPPD1Ev > 000000000023af40 V _ZTI20CvCaptureCAM_V4L_CPP > 0000000000033c20 V _ZTS20CvCaptureCAM_V4L_CPP > 000000000023aee0 V _ZTV20CvCaptureCAM_V4L_CPP > 000000000023d174 b _ZZL21icvSetPropertyCAM_V4LP16CvCaptureCAM_V4LidE5width > 000000000023d170 b _ZZL21icvSetPropertyCAM_V4LP16CvCaptureCAM_V4LidE6height > > Questions: > 1) Am I doing it all wrong or can one do like this? > 2) Is there a smart way to use the .so file to get the correct name of > functions?
That library seems to be C++ or a C library compiled with the C++ compiler and it doesn't export functions with C linkage, so you need to make one yourself -- Stelian Ionescu a.k.a. fe[nl]ix Quidquid latine dictum sit, altum videtur. http://common-lisp.net/project/iolib
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