Need to call a function that acts as an interrupt for main code

Question

I am creating a state machine program for my class that acts like a traffic controller. I have 9 cases that simulate traffic light situation (i.e Case 1: Red Light on N-S roads and Yellow lights on E-W roads). I have no issues setting up the cases but my problem is that I need to create a void function that acts within each case and identifies that a button is being pressed and activates an "override" state. Once this "override" is activated, depending on the case; the code will switch to another state. Below is the expected void function I am supposed to replicate

void clockwise(int gpio, int level, uint32_t tick)
{
    if(level == 1) {cycle_direction = 1;}
}

This is what I have:

void emergency(int gpio, int level, uint32_t tick)
{
    if(level == 1)
    {
        override = 1;
    }
}

This is how I am trying to apply it in my code:

case 0:
         {
             if(emergency(BUTTON_LEFT,1,???)) // <----
             {
                     
                     sprintf(command_string,"LCD:CLEAR\n");
                     serial_send_request(serial_handle, command_string, serial_receive_buffer);
                     process_serial_response(serial_receive_buffer);
                     if(serial_device.last_error_code < 0)
                     {
                            display_serial_device_error(serial_device.last_error_code);
                     }
                     printf("Red Light on N-S and E-W roads.\n");
                     sprintf(command_string,"LCD:TEXT:State 1\n");
                     serial_send_request(serial_handle, command_string, serial_receive_buffer);
                     process_serial_response(serial_receive_buffer);
                     if(serial_device.last_error_code < 0)
                     {
                            display_serial_device_error(serial_device.last_error_code);
                     }
                     
                     gpioWrite(LED_RED,1); 
                     sprintf(command_string, "LED:RED:1\n");
                     debug_message(DEBUG_INFO, temp_string);
                     serial_send_request(serial_handle, command_string, serial_receive_buffer);
                     process_serial_response(serial_receive_buffer);
                     if(serial_device.last_error_code < 0)
                     {
                        display_serial_device_error(serial_device.last_error_code);
                     }  
                     gpioSleep(0,3,0);
                     break;
             } 
          }

Long story short, the code should work like this:

if(override_function() = non-active state)
{
 do some stuff
}
else if (override function() = active state)
{
 switch to a different case
}

Does anybody know what I am supposed to use for the 3rd parameter of my function when calling it in the main code? Or does the if statement need to be set up differently?