std::make_any(3)

NAME
std::make_any - std::make_any

Synopsis
   template< class T, class... Args > (1) (since C++17)
   std::any make_any( Args&&... args );
   template< class T, class U, class... Args > (2) (since C++17)
   std::any make_any( std::initializer_list<U> il, Args&&... args );
   Constructs an any object containing an object of type T, passing the provided
   arguments to T's constructor.
   1) Equivalent to return std::any(std::in_place_type<T>,
   std::forward<Args>(args)...);
   2) Equivalent to return std::any(std::in_place_type<T>, il,
   std::forward<Args>(args)...);

Example
// Run this code
 #include <any>
 #include <complex>
 #include <functional>
 #include <iostream>
 #include <string>
 int main()
 {
     auto a0 = std::make_any<std::string>("Hello, std::any!\n");
     auto a1 = std::make_any<std::complex<double>>(0.1, 2.3);
     std::cout << std::any_cast<std::string&>(a0);
     std::cout << std::any_cast<std::complex<double>&>(a1) << '\n';
     using lambda = std::function<void(void)>;
     // Put a lambda into std::any. Attempt #1 (failed).
     std::any a2 = [] { std::cout << "Lambda #1.\n"; };
     std::cout << "a2.type() = \"" << a2.type().name() << "\"\n";
     // any_cast casts to <void(void)> but actual type is not
     // a std::function..., but ~ main::{lambda()#1}, and it is
     // unique for each lambda. So, this throws...
     try {
         std::any_cast<lambda>(a2)();
     }
     catch (std::bad_any_cast const& ex) {
         std::cout << ex.what() << '\n';
     }
     // Put a lambda into std::any. Attempt #2 (successful).
     auto a3 = std::make_any<lambda>([] { std::cout << "Lambda #2.\n"; });
     std::cout << "a3.type() = \"" << a3.type().name() << "\"\n";
     std::any_cast<lambda>(a3)();
 }

Possible output:
 Hello, std::any!
 (0.1,2.3)
 a2.type() = "Z4mainEUlvE_"
 bad any_cast
 a3.type() = "St8functionIFvvEE"
 Lambda #2.

See also
   constructor constructs an any object
                 (public member function)
   any_cast type-safe access to the contained object
   (C++17) (function template)