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ArduinoJSON: How to fix 1 or 0 being printed instead of true/false

arduinojson_boolean_issue.cpp
volatile bool value = true;

DynamicJsonDocument json(1024);
json["ok"] = value;
serializeJson(json, Serial);

This will print {"ok": 1} instead of {"ok": true} due to value being declared volatile (it works with just bool value, it does not work with volatile bool value).

In order to force {"ok": true}, just case value to bool:

arduinojson_boolean_cast.cpp
json["ok"] = (bool)value;

Full example

arduinojson_full_example.cpp
volatile bool value = true;

DynamicJsonDocument json(1024);
json["ok"] = (bool)value;
serializeJson(json, Serial);

 

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