在使用CMake（用于手臂的交叉编译）生成可执行文件并在工具链文件中设置CMAKE_SYSROOT变量时，链接器不会自动查找其他库（已明确链接到）依赖的库（例如'z'和' glib'）。当不使用工具链文件（因此不进行交叉编译）时，不需要在target_link_libraries（）中明确提及这些文件，但是当使用工具链文件时，它们会这样做，否则始终会出现找不到链接器的错误。我想知道为什么会这样。
我的环境的简要说明：
我尝试了以下多种组合：设置CMAKE_LIBRARY_PATH，link_directories等。但是，唯一成功的选项似乎是在target_link_libraries（）命令中添加以下内容：'z dl glib-2.0 pcre'）
下面是错误消息的示例： / aarch64-linux-gnu / bin / ld：警告：/lib/libopencv_core.so.4.0.1所需的libdl.so.2，未找到（尝试使用-rpath或-rpath-link）
然后是指示库中未定义函数的简短列表。此错误是针对libdl.so.2找不到的，还有其他错误。
我的错误输出：
/home/brian/workspace/ddpx_xcompile/gcc-linaro-7.4.1-2019.02-x86_64_aarch64-linux-gnu/bin/../lib/gcc/aarch64-linux-gnu/7.4.1/../../../../aarch64-linux-gnu/bin/ld: warning: libdl.so.2, needed by /home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1, not found (try using -rpath or -rpath-link)
/home/brian/workspace/ddpx_xcompile/gcc-linaro-7.4.1-2019.02-x86_64_aarch64-linux-gnu/bin/../lib/gcc/aarch64-linux-gnu/7.4.1/../../../../aarch64-linux-gnu/bin/ld: warning: libpthread.so.0, needed by /home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1, not found (try using -rpath or -rpath-link)
/home/brian/workspace/ddpx_xcompile/gcc-linaro-7.4.1-2019.02-x86_64_aarch64-linux-gnu/bin/../lib/gcc/aarch64-linux-gnu/7.4.1/../../../../aarch64-linux-gnu/bin/ld: warning: libz.so.1, needed by /home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1, not found (try using -rpath or -rpath-link)
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `pthread_key_create@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `gzeof'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `pthread_setspecific@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `pthread_join@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `pthread_getspecific@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `pthread_key_delete@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `pthread_create@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `dlclose@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `gzrewind'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `dlopen@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `dladdr@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `gzopen'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `dlsym@GLIBC_2.17'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `gzclose'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `gzgets'
/home/brian/workspace/test/crossbuild/test_rootfs/ddpx-rootfs-05172019/home/nvidia/3rd_party_libs/opencv/install-cxx11/lib/libopencv_core.so.4.0.1: undefined reference to `gzputs'
collect2: error: ld returned 1 exit status
CMakeFiles/imshow.dir/build.make:95: recipe for target 'imshow' failed
make[2]: *** [imshow] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/imshow.dir/all' failed
make[1]: *** [CMakeFiles/imshow.dir/all] Error 2
Makefile:83: recipe for target 'all' failed
make: *** [all] Error 2
我的Cmake工具链文件：
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(TARGET_FS "/home/brian/workspace/ddpx_xcompile/ddpx-rootfs-05172019" CACHE STRING "test" FORCE)
set(CMAKE_SYSROOT ${TARGET_FS})
#Tried with and without the ${TARGET_FS} prefix, also tried with all uncommented and all commented
#link_directories(/lib/aarch64-linux-gnu)
#link_directories(/usr/lib)
#link_directories(/usr/lib/aarch64-linux-gnu)
#link_directories(${TARGET_FS}/lib/aarch64-linux-gnu)
#link_directories(${TARGET_FS}/usr/lib)
#link_directories(${TARGET_FS}/usr/lib/aarch64-linux-gnu)
#Did not try too much with these
#set(CMAKE_FIND_ROOT_PATH ${CMAKE_SYSROOT})
#set(CMAKE_FIND_ROOT_PATH ${CMAKE_FIND_ROOT_PATH} ${CMAKE_SYSROOT}/lib/aarch64-linux-gnu)
#Tried with two different compiler versions
set(CROSSBIN /home/brian/workspace/ddpx_xcompile/gcc-linaro-7.4.1-2019.02-x86_64_aarch64-linux-gnu)
#set(CROSSBIN /home/brian/workspace/ddpx_xcompile/gcc-linaro-7.3.1-2018.05-x86_64_aarch64-linux-gnu)
set(CMAKE_CXX_COMPILER "${CROSSBIN}/bin/aarch64-linux-gnu-g++")
set(CMAKE_C_COMPILER "${CROSSBIN}/bin/aarch64-linux-gnu-gcc")
set(CMAKE_AR_COMPILER "${CROSSBIN}/bin/aarch64-linux-gnu-ar")
#This was also an experiment, no change
#set(CMAKE_PREFIX_PATH ${TARGET_FS})
#list(APPEND CMAKE_PREFIX_PATH ${TARGET_FS}/lib/aarch64-linux-gnu)
#list(APPEND CMAKE_PREFIX_PATH /lib/aarch64-linux-gnu)
#list(APPEND CMAKE_LIBRARY_PATH "/lib/aarch64-linux-gnu")
#list(APPEND CMAKE_LIBRARY_PATH "/usr/lib/aarch64-linux-gnu")
#Tried with the 4 below uncommented or just commented
#set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
#set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
#set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
#set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
message(STATUS "CMAKE_LIBRARY_PATH: ${CMAKE_LIBRARY_PATH}")