c++cmakeg++openwrt

The C++ compiler does not support C++11 (e.g. std::unique_ptr) building OpenWrt


I am using instructions here and here to build OpenWrt in Ubuntu, but I am getting:

make[4]: Entering directory '~/openwrt/build_dir/host/cmake-3.11.1/Bootstrap.cmk'
make[4]: 'cmake' is up to date.
make[4]: Leaving directory '~/openwrt/build_dir/host/cmake-3.11.1/Bootstrap.cmk'
loading initial cache file ~/openwrt/build_dir/host/cmake-3.11.1/Bootstrap.cmk/InitialCacheFlags.cmake
CMake Error at CMakeLists.txt:92 (message):
  The C++ compiler does not support C++11 (e.g.  std::unique_ptr).


-- Configuring incomplete, errors occurred!

There was a solution to a similar problem here. However, it is not clear to me which CMakeLists.txt file is the 'root' in my case. I am not seeing much on the OpenWrt forums (or search engines in general) about this fail.

The impression I get is that the CMake installation is downloaded by the OpenWrt builder itself, as I do not have CMake installed and installing CMake resolved nothing.

Tried checking out latest OpenWrt v18.06.2. When that failed to build I deleted the cloned directory and tried v18.06.0-rc2. There was no improvement.

I also tried

export CMAKE_CXX_STANDARD=11

before running 'make', but it did not resolve the issue.

The state of my g++ install:

g++ -v

Output:

Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/x86_64-linux-gnu/7/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 7.3.0-27ubuntu1~18.04' --with-bugurl=file:///usr/share/doc/gcc-7/README.Bugs --enable-languages=c,ada,c++,go,brig,d,fortran,objc,obj-c++ --prefix=/usr --with-gcc-major-version-only --program-suffix=-7 --program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id --libexecdir=/usr/lib --without-included-gettext --enable-threads=posix --libdir=/usr/lib --enable-nls --with-sysroot=/ --enable-clocale=gnu --enable-libstdcxx-debug --enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new --enable-gnu-unique-object --disable-vtable-verify --enable-libmpx --enable-plugin --enable-default-pie --with-system-zlib --with-target-system-zlib --enable-objc-gc=auto --enable-multiarch --disable-werror --with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32 --enable-multilib --with-tune=generic --enable-offload-targets=nvptx-none --without-cuda-driver --enable-checking=release --build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
gcc version 7.3.0 (Ubuntu 7.3.0-27ubuntu1~18.04)

Well, that's five hours, and I'm out of ideas. Could this be a misconfiguration or a bug on the developer end?

If a misconfiguration, what could be set up wrong?


Solution

  • My solution is simply:

    I copied the CMake source code to my system drive. If you make CMake on a remote harddrive it will fail and error just like above.