opencv编译常见问题

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常见问题：

1. 找不到 stdlib.h头文件

/usr/include/c++/7/cstdlib:75:15: fatal error: stdlib.h: No such file
or directory #include_next compilation terminated.

原因： include_next对头文件路径敏感，原因没细查
解决方案：cmake编译时加 -DENABLE_PRECOMPILED_HEADERS=OFF

2. 找不到LAPACKE_H_PATH-NOTFOUND/lapacke.h

/home/zebra/documents/thirdparty/opencv/build/opencv_lapack.h:2:10:
fatal error: LAPACKE_H_PATH-NOTFOUND/lapacke.h: No such file or
directory #include “LAPACKE_H_PATH-NOTFOUND/lapacke.h”
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ compilation terminated.
解决方案：

• sudo apt-get install liblapacke-dev
• 将该文件引用的头文件改为#include “lapacke.h”

3. 未定义的引用`dgeqrf_’
   解决方案：
   https://github.com/opencv/opencv/issues/7970
   cmake编译时加 -DWITH_LAPACK=OFF
   错了就禁用，这什么解决方案啊…

4. error: ‘CODEC_FLAG_GLOBAL_HEADER’ 未声明

error: ‘CODEC_FLAG_GLOBAL_HEADER’ was not declared in this scope
c->flags |= CODEC_FLAG_GLOBAL_HEADER;

解决方案：
opencv/modules/videoio/src/cap_ffmpeg_impl.hpp顶端添加

#define AV_CODEC_FLAG_GLOBAL_HEADER (1 << 22)
#define CODEC_FLAG_GLOBAL_HEADER AV_CODEC_FLAG_GLOBAL_HEADER
#define AVFMT_RAWPICTURE 0x0020