Install OpenCV and compile C program using GCC

Question

As part of a bigger project I am working on, I need to use the OpenCV library on a C program. I installed OpenCV and opencv-devel using yum in Fedora 17 32-bit. I instructed the preprocessor to import opencv/cv.h and opencv/highgui.h, as the necessary header files.

As I've mentioned, gcc is used to compile the whole C project. However, there seems to be a problem with the linker.

Whenever I try to compile the project (gcc opencv.c -o opencv), I get a list of errors, similar to:

/tmp/ccLJWE0c.o: In function `cvRound': opencv.c:(.text+0x19):
undefined reference to `lrint' /tmp/ccLJWE0c.o: In function
`cvDecRefData': opencv.c:(.text+0xa5c): undefined reference to
`cvFree_' opencv.c:(.text+0xacd): undefined reference to `cvFree_'
/tmp/ccLJWE0c.o: In function `cvGetRow': opencv.c:(.text+0xbc3):
undefined reference to `cvGetRows' /tmp/ccLJWE0c.o: In function
`cvGetCol': opencv.c:(.text+0xbee): undefined reference to `cvGetCols'
/tmp/ccLJWE0c.o: In function `cvReleaseMatND': opencv.c:(.text+0xc01):
undefined reference to `cvReleaseMat' /tmp/ccLJWE0c.o: In function
`cvSubS': opencv.c:(.text+0xd21): undefined reference to `cvAddS'
/tmp/ccLJWE0c.o: In function `cvCloneSeq': opencv.c:(.text+0xd6f):
undefined reference to `cvSeqSlice' /tmp/ccLJWE0c.o: In function
`cvSetNew': opencv.c:(.text+0xdce): undefined reference to `cvSetAdd'
/tmp/ccLJWE0c.o: In function `cvGetSetElem': opencv.c:(.text+0xe61):
undefined reference to `cvGetSeqElem' /tmp/ccLJWE0c.o: In function
`cvEllipseBox': opencv.c:(.text+0xf61): undefined reference to
`cvEllipse' /tmp/ccLJWE0c.o: In function `cvFont':
opencv.c:(.text+0xfb1): undefined reference to `cvInitFont'
/tmp/ccLJWE0c.o: In function `cvReadIntByName':
opencv.c:(.text+0x103f): undefined reference to `cvGetFileNodeByName'
/tmp/ccLJWE0c.o: In function `cvReadRealByName':
opencv.c:(.text+0x10d0): undefined reference to `cvGetFileNodeByName'
/tmp/ccLJWE0c.o: In function `cvReadStringByName':
opencv.c:(.text+0x112a): undefined reference to `cvGetFileNodeByName'
/tmp/ccLJWE0c.o: In function `cvReadByName': opencv.c:(.text+0x115a):
undefined reference to `cvGetFileNodeByName' opencv.c:(.text+0x1170):
undefined reference to `cvRead' /tmp/ccLJWE0c.o: In function
`cvCreateSubdivDelaunay2D': opencv.c:(.text+0x11a3): undefined
reference to `cvCreateSubdiv2D' opencv.c:(.text+0x11cd): undefined
reference to `cvInitSubdivDelaunay2D' /tmp/ccLJWE0c.o: In function
`cvContourPerimeter': opencv.c:(.text+0x1307): undefined reference to
`cvArcLength' /tmp/ccLJWE0c.o: In function `cvCalcHist':
opencv.c:(.text+0x132f): undefined reference to `cvCalcArrHist'
/tmp/ccLJWE0c.o: In function `main': opencv.c:(.text+0x14cd):
undefined reference to `cvCreateImage' opencv.c:(.text+0x1510):
undefined reference to `cvGet2D' opencv.c:(.text+0x159e): undefined
reference to `cvSet2D' opencv.c:(.text+0x15df): undefined reference to
`cvSaveImage' collect2: error: ld returned 1 exit status

Also, when I compile the program using:

gcc opencv.c -o opencv `pkg-config --libs --cflags opencv` -ldl

I still get:

/usr/bin/ld: /tmp/ccMRviO3.o: undefined reference to symbol 'lrint@@GLIBC_2.1'
/usr/bin/ld: note: 'lrint@@GLIBC_2.1' is defined in DSO /lib/libm.so.6 so try adding it to the linker command line
/lib/libm.so.6: could not read symbols: Invalid operation
collect2: error: ld returned 1 exit status

I've been trying to find a solution, but nothing seems to fix the problem. In the OpenCV Documentation, they mention a different way of installing the libraries needed, but I don't really understand the steps I have to follow. I thought that Fedora devel Packages where compiled and ready to use. Anyway, if this is the problem, is there an easy way to make the whole thing work?

I've been coding in Visual Basic for 6 years now, but I've just started learning C as part of my University Education; thus I am not very experienced in manipulating GCC. :( I would ask you to be as explanatory as possible! :)

Any help is appreciated! Thanks in Advance!!! :D

Answer 1

Try adding -lm, to include the math library that provides lrint (see here)