From 2a68b7b12e5e0f64b4a1c0f5b1d7e8b725aba0c9 Mon Sep 17 00:00:00 2001
From: Raphael Riebl <raphael.riebl@thi.de>
Date: Tue, 23 Jan 2018 21:22:50 +0100
Subject: [PATCH] cmake: add pthread dependency explicitly when linking to a
 Boost library

Change-Id: I36695dfcaf58bef5e6b9738432f9a1e695f68d70
---
 CMakeLists.txt                      | 5 +++++
 cmake/GoogleTestTargets.cmake       | 9 ++++++---
 cmake/VanetzaConfig.cmake.in        | 5 +++++
 cmake/VanetzaExportsConfig.cmake.in | 1 +
 vanetza/common/CMakeLists.txt       | 4 ++++
 5 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3307af772..fc00c2fc1 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,6 +6,11 @@ set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake)
 set(CMAKE_CXX_STANDARD 11)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 
+# Look up threading library (usually pthread)
+set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
+set(THREADS_PREFER_PTHREAD_FLAG TRUE)
+find_package(Threads MODULE)
+
 # Build configuration
 option(BUILD_USING_CONAN "Build with conan package manager" OFF)
 if(BUILD_USING_CONAN)
diff --git a/cmake/GoogleTestTargets.cmake b/cmake/GoogleTestTargets.cmake
index fccfe334c..fb9a5390a 100644
--- a/cmake/GoogleTestTargets.cmake
+++ b/cmake/GoogleTestTargets.cmake
@@ -40,9 +40,12 @@ target_link_libraries(${GTest_MAIN_LIBRARY} PUBLIC ${GTest_LIBRARY})
 add_dependencies(${GTest_MAIN_LIBRARY} extract_gtest)
 
 # Look for threading library and configure GTest accordingly
-set(CMAKE_THREAD_PREFER_PTHREAD True)
-set(THREADS_PREFER_PTHREAD_FLAG True)
-find_package(Threads QUIET)
+if(NOT DEFINED CMAKE_USE_PTHREADS_INIT)
+    set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
+    set(THREADS_PREFER_PTHREAD_FLAG TRUE)
+    find_package(Threads MODULE)
+endif()
+
 if(CMAKE_USE_PTHREADS_INIT)
     message(STATUS "Build GTest with pthread support")
     target_compile_definitions(${GTest_LIBRARY} PUBLIC "GTEST_HAS_PTHREAD=1")
diff --git a/cmake/VanetzaConfig.cmake.in b/cmake/VanetzaConfig.cmake.in
index d2004f306..a98fda10f 100644
--- a/cmake/VanetzaConfig.cmake.in
+++ b/cmake/VanetzaConfig.cmake.in
@@ -8,6 +8,7 @@ include(MacroFindDependencyComponents)
 
 find_dependency_components(Boost VERSION @Boost_MAJOR_VERSION@.@Boost_MINOR_VERSION@ COMPONENTS @Boost_COMPONENTS@)
 find_dependency(GeographicLib @GeographicLib_VERSION_STRING@)
+find_dependency(Threads)
 
 if(@CryptoPP_FOUND@)
     find_dependency(CryptoPP @CryptoPP_VERSION_STRING@)
@@ -25,6 +26,10 @@ if(@OPENSSL_FOUND@)
     find_dependency(OpenSSL ${OPENSSL_VERSION_WITHOUT_PATCH})
 endif()
 
+if(@THREADS_FOUND@)
+    find_dependency(Threads)
+endif()
+
 # Restore previous module path
 list(REMOVE_AT CMAKE_MODULE_PATH -1)
 
diff --git a/cmake/VanetzaExportsConfig.cmake.in b/cmake/VanetzaExportsConfig.cmake.in
index 98d52f955..31915305b 100644
--- a/cmake/VanetzaExportsConfig.cmake.in
+++ b/cmake/VanetzaExportsConfig.cmake.in
@@ -8,6 +8,7 @@ find_dependency_components(Boost VERSION @Boost_MAJOR_VERSION@.@Boost_MINOR_VERS
 include(CompatBoostTargets)
 
 find_dependency(GeographicLib @GeographicLib_VERSION_STRING@)
+find_dependency(Threads)
 
 if(@CryptoPP_FOUND@)
     find_dependency(CryptoPP @CryptoPP_VERSION_STRING@)
diff --git a/vanetza/common/CMakeLists.txt b/vanetza/common/CMakeLists.txt
index 40f81c079..b41e23fed 100644
--- a/vanetza/common/CMakeLists.txt
+++ b/vanetza/common/CMakeLists.txt
@@ -12,5 +12,9 @@ target_link_libraries(common
     PUBLIC Boost::date_time
     INTERFACE Boost::serialization)
 
+if(TARGET Threads::Threads)
+    target_link_libraries(common INTERFACE Threads::Threads)
+endif()
+
 add_test_subdirectory(tests)