Question

I am compiling a program with the following flags and getting errors (running 64 bit os):

g++ -lm -lml -lcvaux -lhighgui -lcv -lcxcore main.o BRIEF.o -o BRIEF_demo

I get a bunch of undefined references:

main.cpp:(.text+0x1f6): undefined reference to `cvInitMatHeader'

main.cpp:(.text+0x218): undefined reference to cvInitMatHeader'
main.o: In function_Z14drawQuadrangleP9_IplImageiiiiiiii8CvScalari.constprop.77′:
main.cpp:(.text+0x2d5): undefined reference to cvLine'
main.cpp:(.text+0x333): undefined reference tocvLine’
main.cpp:(.text+0x398): undefined reference to cvLine'
main.cpp:(.text+0x3f2): undefined reference tocvLine’

Anyone have an idea how to circumvent this?

Answer 1

I suppose you are using the newest OpenCV 2.3.x. cvInitMatHeader() and cvLine() are actually defined in libcxcore.so, which I can see you are including.

My guess is that the order of the linking is wrong, so you need to adjust your command to something like:

g++ main.cpp BRIEF.cpp -o BRIEF_demo -lm -lml -lcvaux -lhighgui -lcv -lcxcore