• If I take the code as is with the "bool" func pointer on line 17, and compile this in the arduino editor, this also compiles. (as well as in the Visual C++ compiler)
• If I uncomment line 16 and comment line 17 the project builds.

Code

// Test program
bool (*f)(char[], int&) = nullptr;

void setup()
{
    // Initialize serial port
    Serial.begin(9600);
    Serial.println("Started Arduino!");
}

void loop()
{

}

//void ReceiveJSONCommand(int (*ff)(char[], int&))
void ReceiveJSONCommand(bool (*ABC)(char[], int&))
{
    //
}