Method 1

PROJECT(HELLO)
set(CMAKE_CXX_FLAGS "${CAMKE_CXX_FLAGS} -std=c++11")
AUX_SOURCE_DIRECTORY(. SRC_LIST)
ADD_EXECUTABLE(hello ${SRC_LIST})

From the cmakelists.txt file of cmake, we can see that cmake has – STD = C + + 11, just like G + + uses C + + 11, so we can add – pthread to solve it

PROJECT(HELLO)
set(CMAKE_CXX_FLAGS "${CAMKE_CXX_FLAGS} -std=c++11 -pthread")
AUX_SOURCE_DIRECTORY(. SRC_LIST)
ADD_EXECUTABLE(hello ${SRC_LIST})

Method 2

Using package threads and link ${cmake_ THREAD_ LIBS_ INIT}

PROJECT(HELLO)
set(CMAKE_CXX_FLAGS "${CAMKE_CXX_FLAGS} -std=c++11")
FIND_PACKAGE(Threads)
AUX_SOURCE_DIRECTORY(. SRC_LIST)
ADD_EXECUTABLE(hello ${SRC_LIST})
TARGET_LINK_LIBRARIES(hello ${CMAKE_THREAD_LIBS_INIT})