find library,ld library path

例子

#在HINTS后的路径中找NvInfer.h, PATH_SUFFIXES：在每个搜索路径的子目录下搜索
find_path(TENSORRT_INCLUDE_DIR NvInfer.h
HINTS ${TENSORRT_ROOT} ${CUDA_TOOLKIT_ROOT_DIR}
PATH_SUFFIXES include)
find_library(TENSORRT_INFER libnvinfer.so
HINTS ${TENSORRT_ROOT} ${CUDA_TOOLKIT_ROOT_DIR}
PATH_SUFFIXES lib lib64 lib/x64)
find_library(TENSORRT_INFER_PLUGIN libnvinfer_plugin.so
HINTS ${TENSORRT_ROOT} ${CUDA_TOOLKIT_ROOT_DIR}
PATH_SUFFIXES lib lib64 lib/x64)

后面使用的时候：
target_link_libraries(trt ${TENSORRT_INFER} ${TENSORRT_INFER_PLUGIN})

也可以在同时找多个.h / .so文件
find_library(TENSORRT_INFER libnvinfer.so B.so C.so
HINTS ${TENSORRT_ROOT} ${CUDA_TOOLKIT_ROOT_DIR}
PATH_SUFFIXES lib lib64 lib/x64)

2. find_path 会用最后搜索到的结果
比如，我安装了两个eigen3，一个通过apt-get，安装在usr/include, 一个手动编译，在usr/local/include, 用find_path时返回usr/local/include路径

find_path(EIGEN3_INCLUDE_DIR NAMES signature_of_eigen3_matrix_library PATHS include ${EIGEN_ADDITIONAL_SEARCH_PATHS} ${KDE4_INCLUDE_DIR} PATH_SUFFIXES eigen3 eigen )

这里的EIGEN3_INCLUDE_DIR=/usr/local/include