Android CMake build adding no-exceptions and no-rtti by default

Issue

I'm attempting to convert an existing Android.mk based build to CMake and I'm having difficulty building CPP code with exceptions and rtti. The cpp build command generated contains -fno-exceptions and -fno-rtti by default. Adding them as ANDROID_CPP_FEATURES or as cppFlags only appends them to the build command after the default options and the build still fails.

I've searched quite a bit and aside from the few pages pertaining to CMake on Android, I get mostly old Android.mk results from the search.

There is nothing special in any of the CMakeLists.txt file, nothing that would add those options as I can tell.

None of the uncommented options below work.

build.gradle:

    externalNativeBuild {
        cmake {
            arguments '-DANDROID_TOOLCHAIN=gcc',
                       '-DANDROID_PLATFORM=android-19',
                     //  '-DANDROID_STL_FORCE_FEATURES=ON',
                       '-DANDROID_STL=gnustl_static'
                     //'-DANDROID_CPP_FEATURES=rtti'
                     //'-DANDROID_CPP_FEATURES=exceptions',

            cppFlags "-fexceptions -frtti"
            targets  'library2'
        }

    }

Options in build command:

   <removed content> -g -DANDROID -ffunction-sections -funwind-tables -fstack-protector-strong -no-canonical-prefixes -Wa,--noexecstack -Wformat -Werror=format-security -fno-exceptions -fno-rtti -frtti -fexceptions -frtti -O2 -DNDEBUG  -fPIC -MD -MT <additional content>

Solution

Seems like the cppFlags do enable both the exceptions and rtti even if all four options are on the command line. I was seeing a different error.

Answered By - Gary Bak