我试图在基于ARM-linux的系统上编译OPENCV。为此，我创建了一个工具链cmake文件，其中包含以下选项
SET (CMAKE_SYSTEM_NAME Linux)
SET (CMAKE_SYSTEM_VERSION 1)
SET (CMAKE_SYSTEM_PROCESSOR arm)
SET (CMAKE_C_COMPILER "/usr/local/arm/4.3.1-eabi-armv6/usr/bin/arm-linux-gcc")
SET (CMAKE_CXX_COMPILER "/usr/local/arm/4.3.1-eabi-armv6/usr/bin/arm-linux-g++")
SET (CMAKE_FIND_ROOT_PATH "/usr/local/arm/4.3.1-eabi-armv6/")
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 (LIBRARY_OUTPUT_PATH "/home/xxx/OpenCV-2.4.3/lib")
SET (OPENCV_CONFIG_FILE_INCLUDE_DIR "/home/xxx/OpenCV-2.4.3")
SET (OPENCV_WARNINGS_ARE_ERRORS OFF)
运行cmake命令和make命令后，我得到以下错误:
In file included from /usr/local/arm/4.3.1-eabi-armv6/usr/bin-ccache/../lib/gcc/arm-samsung-linux-gnueabi/4.3.1/../../../../arm-samsung-linux-gnueabi/include/c++/4.3.1/bits/postypes.h:47,
from /usr/local/arm/4.3.1-eabi-armv6/usr/bin-ccache/../lib/gcc/arm-samsung-linux-gnueabi/4.3.1/../../../../arm-samsung-linux-gnueabi/include/c++/4.3.1/iosfwd:47,
from /usr/local/arm/4.3.1-eabi-armv6/usr/bin-ccache/../lib/gcc/arm-samsung-linux-gnueabi/4.3.1/../../../../arm-samsung-linux-gnueabi/include/c++/4.3.1/ios:44,
from /usr/local/arm/4.3.1-eabi-armv6/usr/bin-ccache/../lib/gcc/arm-samsung-linux-gnueabi/4.3.1/../../../../arm-samsung-linux-gnueabi/include/c++/4.3.1/ostream:45,
from /usr/local/arm/4.3.1-eabi-armv6/usr/bin-ccache/../lib/gcc/arm-samsung-linux-gnueabi/4.3.1/../../../../arm-samsung-linux-gnueabi/include/c++/4.3.1/iostream:45,
from /home/zwang/OpenCV-2.4.3/3rdparty/openexr/Half/half.h:88,
from /home/zwang/OpenCV-2.4.3/3rdparty/openexr/Half/half.cpp:48:
/usr/local/arm/4.3.1-eabi-armv6/usr/bin-ccache/../lib/gcc/arm-samsung-linux-gnueabi/4.3.1/../../../../arm-samsung-linux-gnueabi/include/c++/4.3.1/cwchar:52:24: error: wchar.h: No such file or directory
总结:编译器无法找到wchar.h, stdio.h, wctype.h, ctype.h。这些头文件位于/usr/local/arm/4.3.1-eabi-armv6/usr/include中。我想我需要使用cmake选项包括这个文件夹。我该怎么做呢?
您可以通过include_directories命令:
include_directories(SYSTEM /usr/local/arm/4.3.1-eabi-armv6/usr/include)
一个更健壮的解决方案是在这个路径中搜索头文件，如果找到了包含该目录，否则失败。除了比在CMakeLists.txt中硬编码本地路径更健壮之外，另一个好处是它在CMake运行时失败，而不是在以后的构建时失败。这最好使用find_path。
例如，您可以这样做:
find_path(WcharPath wchar.h PATHS /usr/local/arm/4.3.1-eabi-armv6/usr/include)
if(WcharPath)
include_directories(SYSTEM ${WcharPath})
else()
message(FATAL_ERROR "Failed to find wchar.h")
endif()
可以设置CMAKE_SYSROOT来解决这个问题。看起来你应该把它设置为
/usr/local/arm/4.3.1-eabi-armv6/
http://www.cmake.org/cmake/help/v3.0/manual/cmake-toolchains.7.html交叉编译
您可以将CMAKE_INCLUDE_PATH设置为环境变量，有关格式的说明请参见CMAKE文档: