如何使用CMake在同一级别构建一个包含两个目录的可执行文件

Question

我需要编译一个可执行文件，其中包括client和common目录中的所有源文件

\root
 \client
   *.cpp
   *.h
   CMakeLists.txt
 \common
   *.cpp
   *.h

这是我当前的CMakeLists.txt

cmake_minimum_required(VERSION 3.1.0)

project(Client)

set(common_dir ${PROJECT_SOURCE_DIR}/common)

include_directories(${common_dir})


set(CMAKE_CXX_STANDARD 17)

set(CMAKE_AUTOMOC ON)
set(CMAKE_AUTORCC ON)
set(CMAKE_AUTOUIC ON)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")

#set(CMAKE_BUILD_TYPE RELEASE)
if (CMAKE_BUILD_TYPE STREQUAL "RELEASE")
    add_definitions(-DQT_NO_DEBUG_OUTPUT)
endif (CMAKE_BUILD_TYPE STREQUAL "RELEASE")


if(CMAKE_VERSION VERSION_LESS "3.7.0")
    set(CMAKE_INCLUDE_CURRENT_DIR ON)
endif()

IF(WIN32)
    SET(OS_SPECIFIC_LIBS netapi32 wsock32)
ENDIF(WIN32)


find_package(Qt5 COMPONENTS Core REQUIRED)
find_package(Qt5 COMPONENTS Widgets REQUIRED)
find_package(Qt5 COMPONENTS Gui REQUIRED)
find_package(Qt5 COMPONENTS Network REQUIRED)
#find_package(Qt5 COMPONENTS Sql REQUIRED)
find_package(Qt5 COMPONENTS Svg REQUIRED)
find_package(Qt5 COMPONENTS PrintSupport REQUIRED)
find_package(Qt5WebSockets REQUIRED)

file(GLOB client_src "*.h" "*.cpp" "Resources.qrc")
file(GLOB common_src "${common_dir}/*.h" "${common_dir}/*.cpp")
add_library(common_src)

add_executable(Client ${common_src} ${client_src})

target_link_libraries(Client ${common_dir} Qt5::Core Qt5::Widgets Qt5::Gui Qt5::Network Qt5::Svg Qt5::PrintSupport Qt5::WebSockets ${OS_SPECIFIC_LIBS})

但是我得到了这个错误：

mingw32-make.exe[3]: *** No rule to make target '../common', needed by 'Client.exe'.  Stop.
mingw32-make.exe[2]: *** [CMakeFiles\Makefile2:126: CMakeFiles/Client.dir/all] Error 2
mingw32-make.exe[1]: *** [CMakeFiles\Makefile2:133: CMakeFiles/Client.dir/rule] Error 2
mingw32-make.exe: *** [Makefile:150: Client] Error 2

Answer 1

任一

删除add_library(common_src)

或

add_library(MyLib ${common_src})
add_executable(Client ${client_src])
target_link_libraries(Client MyLib)

Answer 2

看起来你把很多东西都弄混了。你可以在这里找到源代码(globbing is bad, don't do it)：

file(GLOB client_src "*.h" "*.cpp" "Resources.qrc")
file(GLOB common_src "${common_dir}/*.h" "${common_dir}/*.cpp")

然后在common_src之外创建库

add_library(common_src)

然后使用创建可执行文件，包括 client_src和common_src

add_executable(Client ${common_src} ${client_src})

然后尝试将Client与common_dir链接起来。最后一步没有意义，因为Client中已经有了common_src，不需要将common_dir库链接到它。

因此，您可以简化cmake并执行以下操作(只显示相关部分)：

#...
file(GLOB client_src "*.h" "*.cpp" "Resources.qrc")
file(GLOB common_src "${common_dir}/*.h" "${common_dir}/*.cpp")
# add_library(common_src) # Remove this line

add_executable(Client ${common_src} ${client_src}) # create Client out of common and client src

target_link_libraries(Client Qt5::Core Qt5::Widgets Qt5::Gui Qt5::Network Qt5::Svg Qt5::PrintSupport Qt5::WebSockets ${OS_SPECIFIC_LIBS})

附注：

这两者本质上做的是一样的事情：

set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17") # remove this

相反，我使用set_target_properties重新注释来设置C++标准，而不是上述内容：

set_target_properties(Client PROPERTIES
    CXX_STANDARD 17           # standard version
    CXX_STANDARD_REQUIRED ON  # required yes
)