diff --git a/c/tests/CMakeLists.txt b/c/tests/CMakeLists.txt
index 25b4f5c..457022f 100644
--- a/c/tests/CMakeLists.txt
+++ b/c/tests/CMakeLists.txt
@@ -81,7 +81,7 @@
     option(THREADERCISER "Run the threaderciser concurrency tests" OFF)
     if (THREADERCISER)
       add_executable(c-threaderciser threaderciser.c)
-      set_target_properties(c-threaderciser PROPERTIES COMPILE_FLAGS "${CMAKE_CXX_FLAGS} ${CXX_WARNING_FLAGS}")
+      set_target_properties(c-threaderciser PROPERTIES COMPILE_FLAGS "${CMAKE_C_FLAGS} ${C_WARNING_FLAGS}")
       add_test(NAME c-threaderciser COMMAND ${test_env} ${TEST_EXE_PREFIX_CMD} $<TARGET_FILE:c-threaderciser>)
       set_tests_properties(c-threaderciser PROPERTIES WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
       target_link_libraries (c-threaderciser qpid-proton-proactor)