Invalid use of incomplete type in android ndk using c++11 std::async

Question

I tried to use the following function to check whether std::async is supported in android ndk with Eclipse along with cygwin in windows. The function I used is the following

Machine: 64bit win 8 with cygwin

Android: r8e

Eclipse: Juno 4.2.1

ADT: 22.0.1

struct Foo
{
Foo() : data(0) {}
void sum(int i) { data +=i;}
int data;
};

int main()
{
  Foo foo;

  auto f = std::async(&Foo::sum, &foo, 42);
  f.get();
  std::cout << foo.data << "\n";
}

I get the following error:

Description Resource Path Location Type invalid use of incomplete type 'std::__async_sfinae_helper::type {aka struct std::future}' Sample.cpp /Cli13/jni line 63 C/C++ Problem

Note: I have set the _GLIBCXX_HAS_GTHREADS and also the GXX_EXPERIMENTAL_CXX0X along with the ATOMIC_INT_LOCK_FREE... By default the ndk uses 4.6 toolchain. I had to include the gnu-libstd++ for 4.7 manually in Properties-> C/C++ -> Includes. Is there any work around to make the std::async working???

Thank You.

Answer 1

Android NDK r8e does not have the full run-time library support of C++11. You will need to compile your own NDK using some third-party stdlib or wait Google to include the Clang 3.3 in the NDK which is C++11 feature-complete.