File principale:

#define CONNECT true

#include <ESP8266WiFi.h>
#include <ArduinoOTA.h>
#include <RTClib.h>

#include "Dichiarazioni.h"
#include "FunzioniNet.cpp"

void setup() {
  Serial.begin(115200);
  delay(200);
  Serial.println("\n\nMem1:" + String(ESP.getFreeHeap()));
  Serial.println("Sketch:"+String(ESP.getFreeSketchSpace()));
  rtc.begin(DateTime(F(__DATE__), F(__TIME__)));

 Connected=Connect();
}

void loop() {

}

FILE FunzioniNet.cpp

bool Connect()
{
  bool Conn = false;
  if (!CONNECT) return false;

<eccetera>