link to pthread library using CMake (in CLion)

Question

I've looked all over and I can't figure out how to get CLion to link the lpthread library. I know that w/ gcc you can just type -lpthread, but I need to do some debugging in CLion.

Here's my current CMakeLists file:

cmake_minimum_required(VERSION 3.3)

project(lab4)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")

include_directories(/usr/include/)
link_directories(/usr/include/)

set(SOURCE_FILES lab4_v2.c)
add_executable(lab4 ${SOURCE_FILES})

This is about CMake, and not about makefile or CLion... – Chris Maes Dec 02 '15 at 16:49 — Chris Maes, Dec 02 '15 at 16:49

score 33 · Accepted Answer · edited Aug 09 '19 at 00:56

Before CMake 2.8.12:

find_package(Threads REQUIRED)
if(THREADS_HAVE_PTHREAD_ARG)
  set_property(TARGET my_app PROPERTY COMPILE_OPTIONS "-pthread")
  set_property(TARGET my_app PROPERTY INTERFACE_COMPILE_OPTIONS "-pthread")
endif()
if(CMAKE_THREAD_LIBS_INIT)
  target_link_libraries(my_app "${CMAKE_THREAD_LIBS_INIT}")
endif()

If you have CMAKE 2.8.12+:

find_package(Threads REQUIRED)
if(THREADS_HAVE_PTHREAD_ARG)
  target_compile_options(my_app PUBLIC "-pthread")
endif()
if(CMAKE_THREAD_LIBS_INIT)
  target_link_libraries(my_app "${CMAKE_THREAD_LIBES_INIT}")
endif()

If you have CMake 3.1.0+

set(THREADS_PREFER_PTHREAD_FLAG ON)
find_package(Threads REQUIRED)
target_link_libraries(my_app Threads::Threads)

If you want to use one of the first two methods with CMake 3.1+, you will need:

set(THREADS_PREFER_PTHREAD_FLAG ON)

Info taken from video by Anastasia Kazakova

score 25 · Answer 2 · answered May 22 '17 at 07:53

25

For C:

set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")

answered May 22 '17 at 07:53

Soner from The Ottoman Empire

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score 21 · Answer 3 · answered Dec 02 '15 at 16:47

21

you should use target_link_libraries:

target_link_libraries(lab4 pthread)

answered Dec 02 '15 at 16:47

Chris Maes

35,025
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@somecbusnerd : if my answer helped you, consider accepting it. – Chris Maes Jan 19 '16 at 15:04
Note: might also need to specify `find_package( Threads REQUIRED )` before that (source: http://stackoverflow.com/a/40102044/997940) – Yoav Feuerstein Jan 01 '17 at 12:49

score 4 · Answer 4 · answered Nov 09 '19 at 09:33

4

For C++ use

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++14 -pthread" )

answered Nov 09 '19 at 09:33

dklovedoctor

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only this one worked for me, not the ones mentioned above – Boba0514 Nov 05 '20 at 12:38
The same as the previous one. Can someone explain this please. – raiserle Nov 23 '20 at 09:55

score 3 · Answer 5 · answered Oct 02 '18 at 17:22

Answer as of CLion 2018.2 and the bundled cmake version of 3.12.0

I used other answers in this thread to modify my CMakeLists.txt, and ultimately found I had to add a SECOND line with set() to make this work. My file looks like the following:

cmake_minimum_required(VERSION 3.12)
project(thread_test_project C)

set(CMAKE_C_STANDARD 99)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -pthread")

include_directories(.)

add_executable(thread_test
        thread_test.c)

link to pthread library using CMake (in CLion)

5 Answers5