c++ - How to add "-l" (ell) compiler flag in CMake

Question

Work on Ubuntu 16

I used g++ main.cpp -lpq command for compiler my small project. Now I use Clion and wanna do same what I do with g++. But I can't add compiler flags in cmake file and get compile error.

cmake_minimum_required(VERSION 3.5.1)
project(day_g)

set(CMAKE_CXX_FLAGS "-lpq")

add_definitions(-lpq)

message("CMAKE_CXX_FLAGS is ${CMAKE_CXX_FLAGS}")

set(CMAKE_CXX_STANDARD 11)

set(SOURCE_FILES main.cpp)
add_executable(day_g ${SOURCE_FILES})

Also I run only cmake file and get CMAKE_CXX_FLAGS with -lpq flag.

CMAKE_CXX_FLAGS is -lpq
-- Configuring done
-- Generating done

How properly add compiler flags to cmake file?

Answer 1

Flag -l is for linker, not for compiler. This flag is used for link with libraries. CMake has special command target_link_libraries for that purpose:

target_link_libraries(day_g pq)