g2o库出现undefined reference to错误

g2o库出现undefined reference to错误

---

1.我的CMkeLists.txt

cmake_minimum_required(VERSION 2.6)
project(g2o_learn)

set(CMAKE_CXX_FLAGS "-std=c++11")

include_directories("/usr/include/eigen3")
find_package(g2o REQUIRED)
include_directories(${g2o_INCLUDE_DIRS})
find_package( OpenCV REQUIRED )                          
include_directories(${OpenCV_INCLUDE_DIRS})

add_executable(g2o_learn main.cpp)

target_link_libraries( g2o_learn ${OpenCV_LIBRARIES}) 
target_link_libraries(g2o_learn ${g2o_LIBRARIES})
install(TARGETS g2o_learn RUNTIME DESTINATION bin)

在这之后，编译程序的时候，出现undefined reference to错误，基本上所有的g2o的模块都找不到，
解决方法如下

1. 找到下载g2o库的文件夹下，进入cmake_modules文件夹下，找到FINDG2O.cmake，然后复制到cpp目录下的cmake文件夹下，然后修改CMakeList.txt文件，修改后的文件内容如下

cmake_minimum_required(VERSION 2.6)
project(g2o_learn)

set(CMAKE_CXX_FLAGS "-std=c++11")


list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)


include_directories("/usr/include/eigen3")

find_package(g2o REQUIRED)
include_directories(${g2o_INCLUDE_DIRS})
find_package( OpenCV REQUIRED )                          
include_directories(${OpenCV_INCLUDE_DIRS})

add_executable(g2o_learn main.cpp)
target_link_libraries( g2o_learn ${OpenCV_LIBRARIES}) 
#target_link_libraries(g2o_learn ${g2o_LIBRARIES})

target_link_libraries(g2o_learn g2o_core g2o_stuff)
install(TARGETS g2o_learn RUNTIME DESTINATION bin)

Thank for your reading !!!