有关 CMake 错误的问题：没有为目标提供源

Question

我正在尝试使用 cmake 和 eclipse 将 FreeRtos 添加到我的项目中，但出现错误。我运行的是 debian 10，我的 cmake 版本是 3.13.4。cmake 的文件可以在此 git repo中找到。当我运行以下命令时：

frank@debian:~/temp2/build$ cmake ../../temp2/AM335X-FreeRTOS-lwip/ -G"Eclipse CDT4 - Unix Makefiles"

我收到以下错误：

    CMake Error at ProjectIncludes.cmake:46 (add_library):
  No SOURCES given to target: lib_third_party_ti_platform_beaglebone
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:30 (add_library):
  No SOURCES given to target: lib_third_party_ti_utils
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:38 (add_library):
  No SOURCES given to target: lib_third_party_ti_mmcsdlib
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:54 (add_library):
  No SOURCES given to target: lib_third_party_ti_nandlib
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at CMakeLists.txt:15 (add_executable):
  No SOURCES given to target: freeRTOSBBB.elf


CMake Error at ProjectIncludes.cmake:23 (add_library):
  No SOURCES given to target: lib_third_party_ti_drivers
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:115 (add_library):
  No SOURCES given to target:
  lib_third_party_amazon_freertos_kernel_portable_MemMang
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:86 (add_library):
  No SOURCES given to target:
  lib_third_party_amazon_libraries_3rdparty_lwip_src
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:101 (add_library):
  No SOURCES given to target: src_portable_lwip_ports_cpsw_netif
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:106 (add_library):
  No SOURCES given to target: lib_third_party_amazon_freertos_kernel
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:111 (add_library):
  No SOURCES given to target:
  src_portable_FreeRTOS_portable_GCC_ARM_CA8_amm335x
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:65 (add_library):
  No SOURCES given to target: lib_third_party_ti_system_config_armv7a
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:134 (add_library):
  No SOURCES given to target: src_application
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:120 (add_library):
  No SOURCES given to target: src_portable_AM335X
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)


CMake Error at ProjectIncludes.cmake:129 (add_library):
  No SOURCES given to target: src_portable_ported_aws_bufpool
Call Stack (most recent call first):
  CMakeLists.txt:33 (include)

Answer 1

对于我（来自 Google）来说，当 CMaketarget_sources只有PRIVATE源而没有PUBLIC源时，会发生此错误。

我必须至少制作一个PUBLIC源文件：

老的：

target_sources(${PROJECT_NAME}
        PRIVATE
        External/dbscan.cpp

        main.cpp
        )

新的：

target_sources(${PROJECT_NAME}
        PRIVATE
        External/dbscan.cpp

        PUBLIC
        main.cpp
        )

Answer 2

该错误说明了它的含义：没有库的来源。

#adding entries for lib_third_party_ti_mmcsdlib
    include_directories("${PROJECT_SOURCE_DIR}/lib/third_party/ti/mmcsdlib")
    include_directories("${PROJECT_SOURCE_DIR}/lib/third_party/ti/mmcsdlib/include")
    add_library(lib_third_party_ti_mmcsdlib "") # NO SOURCES HERE!!!!
    target_compile_definitions(lib_third_party_ti_mmcsdlib 
        PRIVATE -DBOOT=MMCSD -DCONSOLE=UARTCONSOLE
    )
    subdirs("${PROJECT_SOURCE_DIR}/lib/third_party/ti/mmcsdlib")
    subdirs("${PROJECT_SOURCE_DIR}/lib/third_party/ti/mmcsdlib/include")

您应该阅读有关 cmake 中add_library 的文档。如果您不提供任何源文件，则应将其声明为INTERFACE

add_library(库名称接口)

在这种情况下，不会生成编译目标。否则，您可以将其声明为IMPORTED，然后 cmake 也不会尝试创建编译目标。

对于SHARED，STATIC或者OBJECT你总是需要提供来源。

您应该检查ProjectIncludes.cmake您真正想要做什么：编译新的库或导入它们。