原文地址：http://blog.csdn.net/gatieme/article/details/49080355
項目需求，交叉編譯opencv，並移植到arm中。
在opencv2.0以上的版本編譯都要藉助於cmake工具生成Makefile
2.0一下版本纔是使用configure生成Makefile
請確保宿主機已經安裝cmake和cmake-gui工具，如果請自行安裝sudo apt-get install cmake cmake-qt-gui cmake-curses-gui
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開發環境
開宿主機：Fedora9.0
交叉編譯器：友善之臂arm-linux-gcc4.4.3
自動化編譯工具: cmake version 2.8.12.2
編譯
下載opencv源代碼
項目官網：http://opencv.org/
下載地址：http://opencv.org/downloads.html 
源碼我放置在自己目錄的/opencv/opev3.0.0-src 下
期望的構建目錄在/opencv/opencv3-build 下
期望的安裝目錄是/opt/arm/opencv/opencv3-arm
cmake配置生成makefile
運行cmake的圖形化工具cmake-gui
sudo cmake-gui- 1
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選擇源代碼目錄/opencv/opev3.0.0-src
選擇Build目錄/opencv/opencv3-build，大家根據自己設置配置編譯目錄
點擊Configure或者Generator
選擇Unix Makefiles，
接着選擇Specify options for cross-compiling，
點擊Next，接着開始配置交叉編譯環境的信息
Operating System填寫arm-inux
C Compilers填寫您交叉編譯器arm-linux-gcc命令的地址
C++ Compilers填寫arm-linux-g++的地址
程序庫的Target Root填寫交叉編譯器的bin目錄，
然後點擊Finish，您的配置信息就出來的 
注意默認的安裝路徑爲 修改默認配置，默認安裝目錄爲/usr/local
但是我們交叉編譯的來說並不合適，這樣會替換我們宿主機上原有的庫，
所以我把CMAKE_INSTALL_PREFIX變量改爲/opt/arm/opencv/opencv3-arm
好了最後點擊Configure進行配置，然後點擊Gennerate就會生成Makefile
make編譯並且安裝
sudo make
sudo make install - 1
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出現問題
我們剛纔的配置其實肯定是有問題的，因爲一堆依賴庫沒有配置鏈接參數，但是我們又不知道需要哪些庫，所以我們只能等待出現問題進行解決。
pthread
報錯
Linking CXX executable ../../bin/opencv_test_calib3d
../../lib/libopencv_core.so: undefined reference to `pthread_key_create'
../../lib/libopencv_core.so: undefined reference to `pthread_getspecific'
../../lib/libopencv_ts.so: undefined reference to `pthread_key_delete'
../../lib/libopencv_core.so: undefined reference to `pthread_once'
../../lib/libopencv_core.so: undefined reference to `clock_gettime'
../../lib/libopencv_core.so: undefined reference to `pthread_setspecific'- 1
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很明顯是pthread的庫，
解決
修改/opt/opencv3-build目錄下的CMakeCache.txt CMAKE_EXE_LINKER_FLAGS原來爲空，加上-lpthread
-lrt
dlfcn
問題
undefined reference to `dlerror'
undefined reference to `dlopen'- 1
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解決
CMAKE_EXE_LINKER_FLAGS繼續加上-ldl
parallel_pthreads_set_threads_num
問題
undefined reference to `dlerror'
undefined reference to `dlopen'- 1
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Linking CXX executable ../../bin/opencv_perf_core
../../lib/libopencv_core.so: undefined reference to `parallel_pthreads_set_threads_num(int)'
../../lib/libopencv_core.so: undefined reference to `parallel_pthreads_get_threads_num()'
../../lib/libopencv_core.so: undefined reference to `parallel_for_pthreads(cv::Range const&, cv::ParallelLoopBody const&, double)'
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解決
這個是編譯工具鏈的問題，解決了快一天
後來重要找到了解決方案Fixed compilation of pthread-based parallel_for with gcc 4.4.3
修改modules/core/src/parallel.cpp，自132行開始添加7處刪除5處（+表示要添加，-表示要刪除）
namespace cv
{
ParallelLoopBody::~ParallelLoopBody() {}
+#if defined HAVE_PTHREADS && HAVE_PTHREADS
+ void parallel_for_pthreads(const cv::Range& range, const cv::ParallelLoopBody& body, double nstripes);
+ size_t parallel_pthreads_get_threads_num();
+ void parallel_pthreads_set_threads_num(int num);
+#endif
}
+
namespace
{
#ifdef CV_PARALLEL_FRAMEWORK
@@ -301,7 +307,7 @@ void cv::parallel_for_(const cv::Range& range, const cv::ParallelLoopBody& body,
}
#elif defined HAVE_PTHREADS
- void parallel_for_pthreads(const Range& range, const ParallelLoopBody& body, double nstripes);
+
parallel_for_pthreads(range, body, nstripes);
#else
@@ -361,8 +367,6 @@ int cv::getNumThreads(void)
#elif defined HAVE_PTHREADS
- size_t parallel_pthreads_get_threads_num();
-
return parallel_pthreads_get_threads_num();
#else
@@ -424,8 +428,6 @@ void cv::setNumThreads( int threads )
#elif defined HAVE_PTHREADS
- void parallel_pthreads_set_threads_num(int num);
-
parallel_pthreads_set_threads_num(threads);
#endif