error::make_unique is not a member of ‘std’ - c++

Question

I am trying to compile the following thread pool program posted on code review to test it.
https://codereview.stackexchange.com/questions/55100/platform-independant-thread-pool-v4
But I am getting the errors
threadpool.hpp: In member function ‘std::future<decltype (task((forward<Args>)(args)...))> threadpool::enqueue_task(Func&&, Args&& ...)’:
threadpool.hpp:94:28: error: ‘make_unique’ was not declared in this scope
auto package_ptr = make_unique<task_package_impl<R, decltype(bound_task)>> (std::move(bound_task), std::move(promise));
^
threadpool.hpp:94:81: error: expected primary-expression before ‘>’ token
auto package_ptr = make_unique<task_package_impl<R, decltype(bound_task)>>(std::move(bound_task), std::move(promise));
^
main.cpp: In function ‘int main()’:
main.cpp:9:17: error: ‘make_unique’ is not a member of ‘std’
auto ptr1 = std::make_unique<unsigned>();
^
main.cpp:9:34: error: expected primary-expression before ‘unsigned’
auto ptr1 = std::make_unique<unsigned>();
^
main.cpp:14:17: error: ‘make_unique’ is not a member of ‘std’
auto ptr2 = std::make_unique<unsigned>();
^
main.cpp:14:34: error: expected primary-expression before ‘unsigned’
auto ptr2 = std::make_unique<unsigned>();

Answer 1

make_unique is an upcoming C++14 feature and thus might not be available on your compiler, even if it is C++11 compliant.
You can however easily roll your own implementation:
template<typename T, typename... Args>
std::unique_ptr<T> make_unique(Args&&... args) {
return std::unique_ptr<T>(new T(std::forward<Args>(args)...));
}
(FYI, here is the final version of make_unique that was voted into C++14. This includes additional functions to cover arrays, but the general idea is still the same.)

Answer 2

If you have latest compiler, you can change the following in your build settings:
C++ Language Dialect C++14[-std=c++14]
This works for me.

Answer 3

1.gcc version >= 5
2.CXXFLAGS += -std=c++14
3. #include <memory>

Answer 4

This happens to me while working with XCode (I'm using the most current version of XCode in 2019...). I'm using, CMake for build integration. Using the following directive in CMakeLists.txt fixed it for me:
set(CMAKE_CXX_STANDARD 14).
Example:
cmake_minimum_required(VERSION 3.14.0)
set(CMAKE_CXX_STANDARD 14)
# Rest of your declarations...

Answer 5

In my case I was needed update the std=c++
I mean in my gradle file was this
android {
...
defaultConfig {
...
externalNativeBuild {
cmake {
cppFlags "-std=c++11", "-Wall"
arguments "-DANDROID_STL=c++_static",
"-DARCORE_LIBPATH=${arcore_libpath}/jni",
"-DARCORE_INCLUDE=${project.rootDir}/app/src/main/libs"
}
}
....
}
I changed this line
android {
...
defaultConfig {
...
externalNativeBuild {
cmake {
cppFlags "-std=c++17", "-Wall" <-- this number from 11 to 17 (or 14)
arguments "-DANDROID_STL=c++_static",
"-DARCORE_LIBPATH=${arcore_libpath}/jni",
"-DARCORE_INCLUDE=${project.rootDir}/app/src/main/libs"
}
}
....
}
That's it...

Answer 6

If you are stuck with c++11, you can get make_unique from abseil-cpp, an open source collection of C++ libraries drawn from Google’s internal codebase.