nlohmann::basic_json::boolean_t¶

using boolean_t = BooleanType;

The type used to store JSON booleans.

RFC 8259 implicitly describes a boolean as a type which differentiates the two literals true and false.

To store boolean values in C++, a type is defined by the template parameter BooleanType which chooses the type to use.

Template parameters¶

BooleanType: the type to store booleans. As it is stored directly inside a basic_json value (in a union), it must be a trivially default-constructible, trivially copyable, and trivially destructible type that is convertible to and from bool. See Template Parameter Requirements.

Notes¶

Default type¶

With the default values for BooleanType (bool), the default value for boolean_t is bool.

Storage¶

Boolean values are stored directly inside a basic_json type.

Examples¶

Example

The following code shows that boolean_t is by default, a typedef to bool.

#include <iostream>
#include <iomanip>
#include <nlohmann/json.hpp>

using json = nlohmann::json;

int main()
{
    std::cout << std::boolalpha << std::is_same<bool, json::boolean_t>::value << std::endl;
}

Output:

true

Version history¶

Added in version 1.0.0.