问题描述：

今天学习ZeroMQ, 写了一个HelloWorld的测试程序，cmake的时候，报错Missing variable is: CMAKE_FIND_LIBRARY_PREFIXES

具体CMakeLists.txt内容为：

cmake_minimum_required(VERSION 3.10) find_package(PkgConfig REQUIRED) pkg_check_modules(ZMQ libzmq) link_directories(${ZMQ_LIBRARY_DIRS}) include_directories(${ZMQ_INCLUDE_DIRS}) # set the project name project(HelloWorld) # add the executable add_executable(hello_world_client hello_world_client.cpp) target_link_libraries(hello_world_client ${ZMQ_LIBRARIES}) add_executable(hello_world_server hello_world_server.cpp) target_link_libraries(hello_world_server ${ZMQ_LIBRARIES})

报错信息：

-- Found PkgConfig: /usr/bin/pkg-config (found version "0.29") -- Checking for module 'libzmq' -- Found libzmq, version 4.3.1 CMake Error: Error required internal CMake variable not set, cmake may not be built correctly. Missing variable is: CMAKE_FIND_LIBRARY_PREFIXES CMake Error: Error required internal CMake variable not set, cmake may not be built correctly. Missing variable is: CMAKE_FIND_LIBRARY_SUFFIXES -- The C compiler identification is GNU 8.3.0 -- The CXX compiler identification is GNU 8.3.0 -- Check for working C compiler: /usr/bin/cc -- Check for working C compiler: /usr/bin/cc -- works -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Detecting C compile features -- Detecting C compile features - done -- Check for working CXX compiler: /usr/bin/c++ -- Check for working CXX compiler: /usr/bin/c++ -- works -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Detecting CXX compile features -- Detecting CXX compile features - done -- Configuring incomplete, errors occurred! See also "/home/lammork/Desktop/zeromq_demo/build/CMakeFiles/CMakeOutput.log".

问题根因：

findpackage() 应该在 project()之后

问题解决：

修改CMakeLists.txt

cmake_minimum_required(VERSION 3.10) # set the project name project(HelloWorld) find_package(PkgConfig REQUIRED) pkg_check_modules(ZMQ libzmq) link_directories(${ZMQ_LIBRARY_DIRS}) include_directories(${ZMQ_INCLUDE_DIRS}) # add the executable add_executable(hello_world_client hello_world_client.cpp) target_link_libraries(hello_world_client ${ZMQ_LIBRARIES}) add_executable(hello_world_server hello_world_server.cpp) target_link_libraries(hello_world_server ${ZMQ_LIBRARIES})