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std::any::has_value

From cppreference.com
< cpp‎ | utility‎ | any
 
 
Utilities library
General utilities
Relational operators (deprecated in C++20)
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bool has_value() const noexcept;
(since C++17)

Checks whether the object contains a value.

[edit] Parameters

(none)

[edit] Return value

true if and only if the instance contains a value.

[edit] Example

Run this code
#include <any>
#include <cassert>
#include <string>
 
int main()
{
 std::any a0;
 assert (a0.has_value() == false);
 
 std::any a1 = 42;
 assert (a1.has_value() == true);
 assert (std::any_cast <int>(a1) == 42);
 a1.reset();
 assert (a1.has_value() == false);
 
 auto a2 = std::make_any <std::string >("Andromeda");
 assert (a2.has_value() == true);
 assert (std::any_cast <std::string &>(a2) == "Andromeda");
 a2.reset();
 assert (a2.has_value() == false);
}

[edit] See also

destroys contained object
(public member function) [edit]
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