收到CMake错误：无法为非项目创建的目标指定链接库
问题描述：
我正在代码中实现CMake，但出现错误
I am implementing CMake in my code but I'm getting the error
无法为目标 Qt5 ::指定链接库：窗口小部件，它不是由项目构建的。
"Cannot specify link libraries for target "Qt5::Widgets" which is not built by the project".
以下是CMakeLists.txt的内容：
Below are the contents of the CMakeLists.txt:
#Specify the version being used aswell as the language
cmake_minimum_required(VERSION 2.6)
#Name your project here
project(eCAD)
#Sends the -std=c++11 flag to the gcc compiler
ADD_DEFINITIONS(-std=c++11)
#This tells CMake to main.cpp and name it eCAD
add_executable(eCAD main.cpp)
#include the subdirectory containing our libs
add_subdirectory (gui)
include_directories(gui)
#include Qt directories
find_package(Qt5Widgets)
find_package(Qt5Core)
find_package(Qt5Designer)
SET(QT_USE_QTDESIGNER ON)
#link_libraries
target_link_libraries(Qt5::Widgets Qt5::Core)
答
target_link_libraries 的第一个参数是目标名称：
The first argument of target_link_libraries is the target name:
target_link_libraries(eCAD Qt5::Widgets Qt5::Core)