cmake: undefined reference to any pcap functions - c++

Question

I want to use pcap in my Clion project on linux.
I installed libpcap-dev:
sudo apt-get install libpcap-dev
But then I try to compile any file, containing pcap functions like:
#include <stdio.h>
#include <pcap.h>
int main(int argc, char *argv[])
{
char *dev, errbuf[PCAP_ERRBUF_SIZE];
dev = pcap_lookupdev(errbuf);
if (dev == NULL) {
fprintf(stderr, "Couldn't find default device: %s\n", errbuf);
return(2);
}
printf("Device: %s\n", dev);
return(0);
}
I have cmake errors:
CMakeFiles/main.cpp.o: In function `main':
/main.cpp:8: undefined reference to `pcap_lookupdev'
I have not used cmake before. Cmake file:
cmake_minimum_required(VERSION 3.7)
project(mypr)
set(CMAKE_CXX_STANDARD 11)
set(SOURCE_FILES main.cpp)
add_executable(mypr ${SOURCE_FILES})

Answer 1

You should include and use a FindPCAP.cmake file to your CMakeLists.txt. Here is one: https://github.com/bro/cmake/blob/master/FindPCAP.cmake
Put FindPCAP.cmake in your project's source directory and try changing your CMakeLists.txt to:
cmake_minimum_required(VERSION 3.7)
project(mypr)
set(CMAKE_CXX_STANDARD 11)
include(FindPCAP.cmake)
set(SOURCE_FILES main.cpp)
add_executable(mypr ${SOURCE_FILES})
target_link_libraries(mypr ${PCAP_LIBRARY})

Answer 2

I think you can also use CMAKE_MODULE_PATH (assume FindPCAP.cmake is in your project's source directory):
cmake_minimum_required(VERSION 3.7)
project(mypr)
set(CMAKE_CXX_STANDARD 11)
set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${PROJECT_SOURCE_DIR}/")
find_package(PCAP REQUIRED)
set(SOURCE_FILES main.cpp)
add_executable(mypr ${SOURCE_FILES})
target_link_libraries(mypr ${PCAP_LIBRARY})

Answer 3

I have encounted with a problem similar to this, when I tried to complied with libpcap by ros catkin_make
CMakeFiles/decode_pcap.dir/src/decode_pcap.cpp.o：在函数‘main’中：
decode_pcap.cpp:(.text+0x130)：对‘pcap_open_live’未定义的引用
decode_pcap.cpp:(.text+0x1b3)：对‘pcap_next’未定义的引用
decode_pcap.cpp:(.text+0x2a4)：对‘pcap_loop’未定义的引用
decode_pcap.cpp:(.text+0x2e6)：对‘pcap_close’未定义的引用
decode_pcap.cpp:(.text+0x2ff)：对‘pcap_close’未定义的引用
collect2: error: ld returned 1 exit status
at last, I added the absolute path to "libpcap.so" by link_libraries() in CMakeLists.txt,like the below
link_libraries(/usr/lib/x86_64-linux-gnu/libpcap.so.0.8)