c++ - Cmake target_link_libraries 没有链接我的库

Question

我将开始声明我在 Cmake 问题上几乎完全是哑巴。

我有以下用于 Kdevelop 4.1 项目的 CMakeLists.txt:

project(uart)

find_package(KDE4 REQUIRED)
include (KDE4Defaults)

include_directories( ${KDE4_INCLUDES} ${QT_INCLUDES} src/include src/include/QSerialDevce )

add_subdirectory(doc)
add_subdirectory(src)
add_subdirectory(icons)

link_directories(/usr/lib)

find_library(SERIALDEVICE_LIB qserialdeviced)

add_executable(uart ${uart_SRCS})
target_link_libraries(uart ${SERIALDEVICE_LIB})

当我尝试构建我的项目时，我看到:

uart/build> make -j2
-- Found Qt-Version 4.6.3 (using /usr/bin/qmake-qt4)
-- Found X11: /usr/lib64/libX11.so
-- Found KDE 4.5 include dir: /usr/include/kde4
-- Found KDE 4.5 library dir: /usr/lib64/kde4/devel
-- Found the KDE4 kconfig_compiler4 preprocessor: /usr/bin/kconfig_compiler4
-- Found automoc4: /usr/bin/automoc4
CMake Error at CMakeLists.txt:16 (add_executable):
  add_executable called with incorrect number of arguments


CMake Error: Attempt to add link library "/usr/lib/libqserialdeviced.so" to target "uart" which is not built by this project.
-- Configuring incomplete, errors occurred!
make: *** [cmake_check_build_system] Error 1
*** Failed ***

我读到的所有内容都说 add_executable 和 target_link_libraries 应该看起来像我文件的最后两行:

add_executable(uart ${uart_SRCS})
target_link_libraries(uart ${SERIALDEVICE_LIB})

如果我更改这两行 CMakeLists.txt 将其保留为:

project(uart)

find_package(KDE4 REQUIRED)
include (KDE4Defaults)

include_directories( ${KDE4_INCLUDES} ${QT_INCLUDES} src/include src/include/QSerialDevce )

add_subdirectory(doc)
add_subdirectory(src)
add_subdirectory(icons)

link_directories(/usr/lib)

find_library(SERIALDEVICE_LIB qserialdeviced)

target_link_libraries(${SERIALDEVICE_LIB})

我明白了:

uart/build> make -j2
-- Found Qt-Version 4.6.3 (using /usr/bin/qmake-qt4)
-- Found X11: /usr/lib64/libX11.so
-- Found KDE 4.5 include dir: /usr/include/kde4
-- Found KDE 4.5 library dir: /usr/lib64/kde4/devel
-- Found the KDE4 kconfig_compiler4 preprocessor: /usr/bin/kconfig_compiler4
-- Found automoc4: /usr/bin/automoc4
-- Configuring done
-- Generating done
-- Build files have been written to: uart/build
[ 11%] Built target doc-handbook
[ 11%] Built target uart_automoc
Linking CXX executable uart
CMakeFiles/uart.dir/uart.o: In function `uart::setupSerial()':
uart/src/uart.cpp:126: undefined reference to `AbstractSerial::AbstractSerial(QObject*)'
CMakeFiles/uart.dir/uart.o: In function `uart::setupEnumerator()':
uart/src/uart.cpp:108: undefined reference to `SerialDeviceEnumerator::SerialDeviceEnumerator(QObject*)'
CMakeFiles/uart.dir/uart.o: In function `uart::setupSerial()':
uart_/uart/src/uart.cpp:136: undefined reference to `AbstractSerial::enableEmitStatus(bool)'
CMakeFiles/uart.dir/uart.o: In function `uart::setupEnumerator()':
uart_/uart/src/uart.cpp:112: undefined reference to `SerialDeviceEnumerator::setEnabled(bool)'
collect2: ld returned 1 exit status
make[2]: *** [src/uart] Error 1
make[1]: *** [src/CMakeFiles/uart.dir/all] Error 2
make: *** [all] Error 2
*** Failed ***

这清楚地表明 target_link_libraries 没有链接我的 qserialdeviced。

qserialdeviced 位于 /usr/lib/libqserialdeviced.so.1.0.0，正确模拟链接到 /usr/lib/libqserialdeviced.so 如果我手动将它添加到 Makefile 中，很容易找到。

我显然试过了:

target_link_libraries(-lqserialdeviced)

没有变化。

我也试过了:

if ("${SERIALDEVICE_LIB}" STREQUAL "SERIALDEVICE_LIB-NOTFOUND")
    message(FATAL_ERROR "'qserialdeviced' wasn't found!")
else()
    message("'qserialdeviced' found: " ${SERIALDEVICE_LIB})
endif ()

但是这个测试成功了。图书馆找到了:

'qserialdeviced' found: /usr/lib/libqserialdeviced.so

谁能帮我理解这里发生了什么？

我正在使用 Linux Fedora 13、cmake 版本 2.8.0、gcc (GCC) 4.4.5 20101112 (Red Hat 4.4.5-2) 和 kdevelop-4.1.0-1.fc13.x86_64。

谢谢我提前。

---

编辑:

按照@DatChu 的建议，我将 CMakeLists.txt 拆分到我的子目录中，现在一切对我来说都有意义。

谢谢大家!

Answer 1

对于原始的 CMakeLists.txt 文件，问题不在于 target_link_libraries 而在于 add_executable

add_executable(uart ${uart_SRCS})

你在哪里设置你的 uart_SRCS 变量？你有吗

set(uart_SRCS src/blahblah.cpp src/somethingblahblah.cpp)

我认为您可能误解了 add_subdirectory 的作用。它不会在里面添加源文件。它告诉 CMake 进入该文件夹并寻找另一个 CMakeLists.txt。当您的项目文件夹中有子项目时，通常会使用它。

如果你有很多源文件不想手动设置，你也可以这样做

file(GLOB uart_SRCS src/*.cpp src/*.c)

缺点是您需要手动重新运行 CMake 才能检测到新文件。请参阅 Jack 关于为什么这可能不是您想要使用的评论。

您的 CMakeLists.txt 很可能是

project(uart)

find_package(Qt4 REQUIRED)
include (${QT_USE_FILE})
find_package(KDE4 REQUIRED)
include (KDE4Defaults)

include_directories( ${KDE4_INCLUDES} ${QT_INCLUDES} src/include src/include/QSerialDevice )
link_directories(/usr/lib) 

file(GLOB uart_SRCS src/*.cpp src/*.h)
file(GLOB uart_HDRS include/*.h include/QSerialDevice/*.h)

find_library(SERIALDEVICE_LIB qserialdeviced)

add_executable(uart ${uart_SRCS} ${uart_HDRS})
target_link_libraries(uart ${SERIALDEVICE_LIB} ${QT_LIBRARIES})