【发布时间】：2017-12-12 17:09:08
【问题描述】：
有没有办法告诉 CMake 排除某些系统包含路径？
例如，我定义了两次 string.h，一次在 /usr/include/c++/v1 (libc++) 中，一次在 /usr/include/ 中，当我编译时出现以下错误：
error: functions that differ only in their return type cannot be overloaded
因为在每个文件中都找到了char *strchr (const char *__s, int __c)函数。
我只想使用 libc++ 中的那个。
我尝试了set(CMAKE_IGNORE_PATH "/usr/include")，但是当我在详细模式下使用 clang 进行编译时，我仍然看到搜索路径中使用了“/usr/include”。
编辑：
使用以下 CMakeLists.txt
project(my_lib)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -v")
set(SOURCES my_lib.cpp)
add_library(my_lib STATIC ${SOURCES})
set(CMAKE_DEBUG_TARGET_PROPERTIES INCLUDE_DIRECTORIES)
我有这个输出：
[ 50%] Building CXX object CMakeFiles/my_lib.dir/my_lib.cpp.o
clang version 4.0.1-6 (tags/RELEASE_401/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/7.2.0
Selected GCC installation: /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0
Candidate multilib: .;@m64
Selected multilib: .;@m64
"/usr/lib/llvm-4.0/bin/clang" -cc1 -triple x86_64-pc-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -discard-value-names -main-file-name my_lib.cpp -mrelocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -v -dwarf-column-info -debugger-tuning=gdb -coverage-notes-file /media/sf_wncd-app/wasm/cmake/build_linux/CMakeFiles/my_lib.dir/my_lib.cpp.gcno -resource-dir /usr/lib/llvm-4.0/bin/../lib/clang/4.0.1 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0 -internal-isystem /usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward -internal-isystem /usr/include/clang/4.0.1/include/ -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-4.0/bin/../lib/clang/4.0.1/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir /media/sf_wncd-app/wasm/cmake/build_linux -ferror-limit 19 -fmessage-length 228 -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o CMakeFiles/my_lib.dir/my_lib.cpp.o -x c++ /media/sf_wncd-app/wasm/cmake/my_lib.cpp
clang -cc1 version 4.0.1 based upon LLVM 4.0.1 default target x86_64-pc-linux-gnu
ignoring nonexistent directory "/include"
ignoring duplicate directory "/usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0"
ignoring duplicate directory "/usr/include/clang/4.0.1/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0
/usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/x86_64-linux-gnu/c++/7.2.0
/usr/bin/../lib/gcc/x86_64-linux-gnu/7.2.0/../../../../include/c++/7.2.0/backward
/usr/include/clang/4.0.1/include
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
[100%] Linking CXX static library libmy_lib.a
[100%] Built target my_lib
当我使用时：
project(my_lib)
set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -v")
set(SOURCES my_lib.cpp)
set(CMAKE_IGNORE_PATH "/usr/include")
add_library(my_lib STATIC ${SOURCES})
set(CMAKE_DEBUG_TARGET_PROPERTIES INCLUDE_DIRECTORIES)
我得到了完全相同的输出。 /usr/include 还在。我猜 CMAKE_IGNORE_PATH 不适用于系统路径？
【问题讨论】：
-
你能给个minimal reproducible example吗？像这样的东西很难重现。您可以添加
set(CMAKE_DEBUG_TARGET_PROPERTIES INCLUDE_DIRECTORIES)来检查例如如果它来自您的代码或链接包中的某些定义。 -
顺便说一句，我最初的重复函数问题来自使用 clang 编译时
-stdlib=libc++和-fms-compatibility选项的混合。没有这些选项，它编译得很好。 -
我可以在 clang 中使用
-nostdinc来不搜索包含文件的标准系统目录或编译器内置目录。但这取决于编译器。