对符号的未定义引用，但库已链接

Undefined reference to symbol but library is linked

本文关键字：链接 引用 符号 未定义      更新时间：2023-10-16

我试图用opencv 3.0构建一个应用程序，我得到一个"未定义的引用符号错误"

我的问题是这个符号是在我链接到的库中定义的。

编译命令:

g++ -o DisparityMap main.o tools.o emb.o moc_tools.o moc_emb.o -lopencv_highgui -lopencv_core -lopencv_imgproc -lopencv_imgcodecs -lopencv_calib3d -lQtGui -lQtCore -lpthread

我得到的错误:

/usr/bin/ld: twowindow.o: undefined reference to symbol '_ZN2cv6String10deallocateEv'
//usr/local/lib/libopencv_core.so.3.0: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status

但是这个符号实际上是在我链接到的库中定义的:

scanelf -l -s _ZN2cv6String10deallocateEv | grep _ZN2cv6String10deallocateEv
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_objdetect.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_photo.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_core.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_video.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_features2d.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_ml.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_highgui.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_videoio.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_stitching.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_videostab.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_superres.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_flann.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_imgproc.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_imgcodecs.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_calib3d.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_shape.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_objdetect.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_photo.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_core.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_video.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_features2d.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_ml.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_highgui.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_videoio.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_stitching.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_videostab.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_superres.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_flann.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_imgproc.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_imgcodecs.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_calib3d.so.3.0.0 
ET_DYN _ZN2cv6String10deallocateEv /usr/local/lib/libopencv_shape.so.3.0.0

编译命令:

这个不是一个编译命令，它是一个链接命令。

我得到的错误:

错误引用的是twowindow.o，它是而不是链接命令中的。

因此，很难相信错误真的来自您给出的链接命令。

最有可能的是，错误来自于不同的链接命令，并且该链接命令没有-lopencv_core。

在链接库之前，给出带有-L标志的库的路径

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