我在交叉编译ORBSLAM3， 准备用在树莓派4上面。
我想通过rsync 把树莓派的/usr， /lib 存在电脑ubuntu /xx/home/raspberrypi/rootfs/， 然后编译时候全部在这里面找所需要的库文件
小弟cmake不熟， 求大佬指点。
编译过程大致是这样:
1. 用 Toolchain-rpi.cmake 作用在 ORBSLAM3 文件顶层的CMakeLists.txt .
2. 在 CMakeLists.txt, 要用find_package() 找几个第三方库， 比如opencv，Pangolin。 在找pangolin, 这其中涉及到PangolinTargets.cmake，PangolinTargets-release.cmake
下面是顶层的CMakeLists.txt 和PangolinTargets.cmake 里面几个路径的输出
CMAKE_SYSROOT = /home/ethan/raspberrypi/rootfs
CMAKE_PREFIX_PATH = ;/home/ethan/raspberrypi/rootfs/usr/local/lib;/home/ethan/raspberrypi/rootfs/usr/lib/arm-linux-gnueabihf
_IMPORT_PREFIX = /home/ethan/raspberrypi/rootfs/usr/local
感觉情况是这样，find_package()找到的都是/home/ethan/raspberrypi/rootfs/下面的.cmake 文件，但最后具体到库文件时， 还是回到了/usr 下面。
举个例子。
PangolinTargets.cmake 有段是这样的
foreach(target ${_IMPORT_CHECK_TARGETS} )
## IMPORT_CHECK_TARGETS = ##
foreach(file ${_IMPORT_CHECK_FILES_FOR_${target}} )
## target = pangolin ##
## _IMPORT_CHECK_FILES_FOR_pangolin = /usr/local/lib/libpangolin.so ##
## file = /usr/local/lib/libpangolin.so ##
if(NOT EXISTS "${file}" )
message(FATAL_ERROR "The imported target \"${target}\" references the file
\"${file}\"
but this file does not exist. Possible reasons include:
* The file was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and contained
\"${CMAKE_CURRENT_LIST_FILE}\"
but not all the files it references.
")
endif()
endforeach()
unset(_IMPORT_CHECK_FILES_FOR_${target})
endforeach()
unset(_IMPORT_CHECK_TARGETS)
_IMPORT_CHECK_TARGETS， 以及 _IMPORT_CHECK_FILES_FOR_${target}
这些是在PangolinTargets-release.cmake 里面定义的。
如果没有改动的话， file = /usr/local/lib/libpangolin.so， 然后 NOT EXISTS "${file}" 就是true， 于是就会因为/usr下面没有该文件而报错
我不知道除了手动修改PangolinTargets-release.cmake 里面所有的路径，还有什么办法。 opencv 应该也存在相同的问题。 find之后显示版本为树莓派上的opencv3.4， 也就是
/home/ethan/raspberrypi/rootfs 下面的。 但具体到库文件， 比如core.hpp， 还是找的/usr 下面的
然后现在但凡涉及到stdio.h,
/usr/include/opencv2/core/core.hpp:48,
/opt/cross-pi-gcc/arm-linux-gnueabihf/include/c++/8.3.0/cstdio:42,
全部也是用的/usr/include/stdio.h。
我ubuntu 上面的没有bits/libio.h， 这里面编译每次用到stdio.h用到都会报fatal error: bits/libio.h: No such file or directory #include
但说来奇怪， 如果我自己写个待 的小程序， 并不会有问题。
我希望现在编译的时候全用的是/home/ethan/raspberrypi/rootfs/ 下面的文件
编译完了放到板子上， 找共享库之类的能在树莓派的 / 下面。
这里面感觉就是root 不一样， 但怎么写起来有点艰辛啊。。。
下面是PangolinTargets.cmake 的内容
# Generated by CMake
# message ("##CMAKE_SYSROOT = ${CMAKE_SYSROOT} ##")
# message ("##CMAKE_PREFIX_PATH = ${CMAKE_PREFIX_PATH} ##")
if("${CMAKE_MAJOR_VERSION}.${CMAKE_MINOR_VERSION}" LESS 2.5)
message(FATAL_ERROR "CMake >= 2.6.0 required")
endif()
cmake_policy(PUSH)
cmake_policy(VERSION 2.6)
#----------------------------------------------------------------
# Generated CMake target import file.
#----------------------------------------------------------------
# Commands may need to know the format version.
set(CMAKE_IMPORT_FILE_VERSION 1)
# Protect against multiple inclusion, which would fail when already imported targets are added once more.
set(_targetsDefined)
set(_targetsNotDefined)
set(_expectedTargets)
foreach(_expectedTarget pangolin)
list(APPEND _expectedTargets ${_expectedTarget})
if(NOT TARGET ${_expectedTarget})
list(APPEND _targetsNotDefined ${_expectedTarget})
endif()
if(TARGET ${_expectedTarget})
list(APPEND _targetsDefined ${_expectedTarget})
endif()
endforeach()
if("${_targetsDefined}" STREQUAL "${_expectedTargets}")
unset(_targetsDefined)
unset(_targetsNotDefined)
unset(_expectedTargets)
set(CMAKE_IMPORT_FILE_VERSION)
cmake_policy(POP)
return()
endif()
if(NOT "${_targetsDefined}" STREQUAL "")
message(FATAL_ERROR "Some (but not all) targets in this export set were already defined.\nTargets Defined: ${_targetsDefined}\nTargets not yet defined: ${_targetsNotDefined}\n")
endif()
unset(_targetsDefined)
unset(_targetsNotDefined)
unset(_expectedTargets)
# Compute the installation prefix relative to this file.
get_filename_component(_IMPORT_PREFIX "${CMAKE_CURRENT_LIST_FILE}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
get_filename_component(_IMPORT_PREFIX "${_IMPORT_PREFIX}" PATH)
if(_IMPORT_PREFIX STREQUAL "/")
set(_IMPORT_PREFIX "")
endif()
# message ("##_IMPORT_PREFIX = ${_IMPORT_PREFIX} ##}")
##_IMPORT_PREFIX = /home/ethan/raspberrypi/rootfs/usr/local ##
# Create imported target pangolin
add_library(pangolin SHARED IMPORTED)
set_target_properties(pangolin PROPERTIES
INTERFACE_INCLUDE_DIRECTORIES "/usr/include;/usr/include;/usr/include;/usr/local/include/eigen3;${_IMPORT_PREFIX}/include"
INTERFACE_LINK_LIBRARIES "rt;pthread;/usr/lib/arm-linux-gnueabihf/libGL.so;/usr/lib/arm-linux-gnueabihf/libGLU.so;/usr/lib/arm-linux-gnueabihf/libGLEW.so;/usr/lib/arm-linux-gnueabihf/libEGL.so;/usr/lib/arm-linux-gnueabihf/libSM.so;/usr/lib/arm-linux-gnueabihf/libICE.so;/usr/lib/arm-linux-gnueabihf/libX11.so;/usr/lib/arm-linux-gnueabihf/libXext.so;rt;pthread;/usr/lib/arm-linux-gnueabihf/libdc1394.so;/usr/lib/arm-linux-gnueabihf/libpng.so;/usr/lib/arm-linux-gnueabihf/libz.so;/usr/lib/arm-linux-gnueabihf/libjpeg.so;/usr/lib/arm-linux-gnueabihf/libtiff.so;/usr/lib/arm-linux-gnueabihf/libIlmImf.so"
INTERFACE_SYSTEM_INCLUDE_DIRECTORIES "/usr/include;/usr/include;/usr/include;/usr/local/include/eigen3"
)
if(CMAKE_VERSION VERSION_LESS 2.8.12)
message(FATAL_ERROR "This file relies on consumers using CMake 2.8.12 or greater.")
endif()
# Load information for each installed configuration.
# message("## CMAKE_CURRENT_LIST_FILE = ${CMAKE_CURRENT_LIST_FILE}## ")
## CMAKE_CURRENT_LIST_FILE = /home/ethan/raspberrypi/rootfs/usr/local/lib/cmake/Pangolin/PangolinTargets.cmake ##
get_filename_component(_DIR "${CMAKE_CURRENT_LIST_FILE}" PATH)#Sets <_DIR> to a component of <${CMAKE_CURRENT_LIST_FILE}>, where <mode> is PATH:
# message("## _DIR = ${_DIR} ##")
## _DIR = /home/ethan/raspberrypi/rootfs/usr/local/lib/cmake/Pangolin ##
file(GLOB CONFIG_FILES "${_DIR}/PangolinTargets-*.cmake")
# Generate a list of files that match the <"${_DIR}/PangolinTargets-*.cmake"> and store it into the <CONFIG_FILES>
# message("## CONFIG_FILES = ${CONFIG_FILES}##")
## CONFIG_FILES = /home/ethan/raspberrypi/rootfs/usr/local/lib/cmake/Pangolin/PangolinTargets-release.cmake##
foreach(f ${CONFIG_FILES})
include(${f})
endforeach()
# Cleanup temporary variables.
set(_IMPORT_PREFIX)
# message("## IMPORT_CHECK_TARGETS = ${IMPORT_CHECK_TARGETS} ##")
## IMPORT_CHECK_TARGETS = ##
# Loop over all imported files and verify that they actually exist
foreach(target ${_IMPORT_CHECK_TARGETS} )
# message("## IMPORT_CHECK_TARGETS = ${IMPORT_CHECK_TARGETS} ##")
## IMPORT_CHECK_TARGETS = ##
foreach(file ${_IMPORT_CHECK_FILES_FOR_${target}} )
message("## target = ${target} ##")
## target = pangolin ##
message("## _IMPORT_CHECK_FILES_FOR_${target} = ${_IMPORT_CHECK_FILES_FOR_${target}} ##")
## _IMPORT_CHECK_FILES_FOR_pangolin = /usr/local/lib/libpangolin.so ##
message("## file = ${file} ##")
## file = /usr/local/lib/libpangolin.so ##
if(NOT EXISTS "${file}" )
message(FATAL_ERROR "The imported target \"${target}\" references the file
\"${file}\"
but this file does not exist. Possible reasons include:
* The file was deleted, renamed, or moved to another location.
* An install or uninstall procedure did not complete successfully.
* The installation package was faulty and contained
\"${CMAKE_CURRENT_LIST_FILE}\"
but not all the files it references.
")
endif()
endforeach()
unset(_IMPORT_CHECK_FILES_FOR_${target})
endforeach()
unset(_IMPORT_CHECK_TARGETS)
# This file does not depend on other imported targets which have
# been exported from the same project but in a separate export set.
# Commands beyond this point should not need to know the version.
set(CMAKE_IMPORT_FILE_VERSION)
cmake_policy(POP)
