'to_string' is not a member of 'std' while cross compile with android-ndk-11c

[zazd]

When I cross compile with android-ndk-11c,I got the error:
CLBlast/include/internal/clpp11.h:129:70: error: 'to_string' is not a member of 'std'
Someone say that using -std=c++11. But I have find it in the CMakeList.txt:

if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
set(FLAGS "/Ox")
set(FLAGS "${FLAGS} /wd4715")
else ()
set(FLAGS "-O3 -std=c++11")
if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")

I am not familiar with cross compile and ndk. So my cmake configure is:
cmake -DCMAKE_AR=$TOOLCHAIN_DIR/arm-linux-androideabi-ar
-DCMAKE_C_COMPILER=$TOOLCHAIN_DIR/arm-linux-androideabi-gcc
-DCMAKE_CXX_COMPILER=$TOOLCHAIN_DIR/arm-linux-androideabi-g++
-DCMAKE_BUILD_TYPE=Release
-DCMAKE_LINKER=$TOOLCHAIN_DIR/arm-linux-androideabi-ld
-DCMAKE_NM=$TOOLCHAIN_DIR/arm-linux-androideabi-nm
-DCMAKE_OBJCOPY=$TOOLCHAIN_DIR/arm-linux-androideabi-objcopy
-DCMAKE_OBJDUMP=$TOOLCHAIN_DIR/arm-linux-androideabi-objdump
-DCMAKE_RANLIB=$TOOLCHAIN_DIR/arm-linux-androideabi-ranlib
-DCMAKE_STRIP=$TOOLCHAIN_DIR/arm-linux-androideabi-strip
-DCMAKE_INSTALL_PREFIX=$INSTALL_DIR/CLBlast
-DOPENCL_INCLUDE_DIRS=$INSTALL_DIR/MaliOpenCL/include
-DOPENCL_LIBRARIES=$$INSTALL_DIR/MaliOpenCL/lib/libGLES_mali.so $CLBLAST_ROOT

Is that something wrong above or Would you tell me how to solve the problem?

Thank you!

[CNugteren]

I am not too familiar with Android either, but perhaps you can run your build-system in a verbose manner? So after running CMake, you'll probably run something like make or nmake, right? In that case, can you for example run make VERBOSE=1? It will then print out the commands which are actually used, so the first thing to check is whether the -std=c++11 flag is actually missing: perhaps it is some other problem.

[zazd]

I try it. But everything seems ok, and I can not find what wrong with it. However I override "std::to_string" and the same functions such as "stoi", and it works. Thank you for your help.

[CNugteren]

What do you mean, you 'override' them? Did you define and implement those functions yourself? Can you post the complete solution in case other people also encounter this problem? Thanks!

[zazd]

Yes，In cross compile a lot of people encounter the error that 'to_string' is not a member of 'std', the same as "stoi","stof","stod" and so on. Even if they use -std=c++11 to compile these functions, they can not solve it and find nothing about the reason. So I fulfill these functions instead of using them. Because they are too simple. Such as
namespace clblast {
string to_string(int value) {
stringstream stm;
stm << value;
return stm.str();
}
}
to instead of std::to_string(value).

However, I cross-compile CLBlast successfully, but in arm, when running the function, likes CLBlast::Gemm, it failed. I am now looking for the reason. But can CLBlast run in the arm?

[CNugteren]

OK, thanks for the details, hopefully that helps others trying to cross-compile for Android.

The library has been tested on ARM before with success, but I never tried Android. Note that if the used device (Mali, Adreno, ...) is not tuned for, performance might be sub-optimal. But let's first try to get it to work. First step would be to compile the tests (cmake -DTESTS=ON ..) and run them (e.g. ./clblast_test_xaxpy). Can you perhaps open a separate issue and post the results of one or more of the failing tests, along with the device you are targeting?

[CNugteren]

I know it's been a while, but I've now implemented the missing functions (when using GCC's gnustl_static instead of LLVM's c++_static) in the repository. They are in a header which is not included by default: 00b5771.