Error::Make_Unique Is Not a Member of 'Std'

error::make_unique is not a member of ‘std’

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.)

make_unique' is not a member of 'std'

I fixed it by replacing -std=c++17 with set(CMAKE_CXX_STANDARD 17)

Why is compiler giving error while using make_unique with array?

You need

arr = std::make_unique<int[]>(size);

make_unique has a specific documented usage:

template< class T > unique_ptr<T> make_unique( std::size_t size );`

... Constructs an array of the given dynamic size. The array elements are value-initialized. This overload participates in overload resolution only if T is an array of unknown bound. The function is equivalent to:

unique_ptr<T>(new std::remove_extent_t<T>[size]())

Conceptually-speaking¹, you can think of make_unique as being very similar to std::unique_ptr<T>(new T(...)) where ... represents forwarding of the args passed to make_unique. In this case, the usage is analogous to forwarding the one arg to operator new[] (std::size_t size)

¹ The documentation I linked above doesn't say that the arg is forwarded in the array case, and I don't believe the spec does either.

no member named 'make_unique' in namespace 'std'

It seems I resolved the issue. I needed to install libc++-dev and make sure -stdlib=libc++ is in the command line.

Trouble with unique_ptr : not a member of 'std'

CFLAGS is for C compilers. You are using C++ and a C++ compiler. Use CXXFLAGS in your Makefile to set C++ compiler's flags:

NAME    =   plazza

G++ =   g++

CXXFLAGS  =   -W -Wall -Wextra -Werror -std=c++11

SRC =   main.cpp

Since you are setting C flags, C++11 is not enabled because -std=c++11 is not passed to your C++ compiler. If you compiled with a C compiler, the compiler (at least GCC does it AFAIK) would warn about the C++ flag being set on the C compiler. You could use make VERBOSE=1 in these kind of compiler error situations for debugging.

Why is std::make_unique necessary to initialize member std::unique array, and how to work around for C++11?

1. The constructor unique_ptr( pointer p ) is marked explicit, which prevents instances of unique_ptr from being constructed implicitly in array list initialization.

2. std::make_unique is available since C++14.

In C++11 a possible solution to both points is to construct an instance explicitly e.g. std::unique_ptr<Bar>(new Bar( 42, 43 )).

Trouble using std::make_unique with member variable of class

Your issue is nothing to do with the class member, rather its type!

std::make_unique() returns std::unique_ptr for the template type T (i.e. std::unique_ptr of an instance of type T)

template< class T, class... Args >
unique_ptr<T> make_unique( Args&&... args );
^^^^^^^^^^^^^^

The member

CChristianLifeMinistryHtmlView *m_pHtmlPreview;

is a pointer to a CChristianLifeMinistryHtmlView, not a std::unique_ptr. Hence, the type mismatch.

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How do I use make_unique with a member variable of the class?

Therefore, you need to use std::unique_ptr<CChristianLifeMinistryHtmlView> as the type of the m_pHtmlPreview member:

std::unique_ptr<CChristianLifeMinistryHtmlView> m_pHtmlPreview; 
...
m_pHtmlPreview = std::make_unique<CChristianLifeMinistryHtmlView>();

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If it is a long typing, a type alias wouldn't be a bad idea:

using UniqueCLMHView = std::unique_ptr<CChristianLifeMinistryHtmlView>;
UniqueCLMHView m_pHtmlPreview; 
...
m_pHtmlPreview = std::make_unique<CChristianLifeMinistryHtmlView>();

error: ‘unique_ptr’ is not a member of ‘std’

You need to include header where unique_ptr and shared_ptr are defined

#include <memory>

As you already knew that you need to compile with c++11 flag

g++ main.cpp -o run -std=c++11
//                  ^

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