Idea: create a function like String, is possible?

[Attigliuzzo]

Hi. I'm a noob programmer and my question is, we know i can write something like this:

String sendData(String command, const int timeout, boolean debug)
{
    String response = "";  //initialize a String variable named "response". we will use it later.

    Serial.print(command);   //send the AT command to the esp8266 (from ARDUINO to ESP8266).

    long int time = millis(); //get the operating time at this specific moment and save it inside the "time" variable.

    while( (time+timeout) > millis()) //excute only whitin 1 second.
    {      
      while(Serial.available())   //is there any response came from the ESP8266 and saved in the Arduino input buffer?
      {
        char c = Serial.read(); //if yes, read the next character from the input buffer and save it in the "response" String variable.
        response+=c; //append the next character to the response variabl. at the end we will get a string(array of characters) contains the response.
      }  
    }    

    if(debug)  //if the "debug" variable value is TRUE, print the response on the Serial monitor.
    {
      Serial.print(response);
    }    
    return response;  //return the String response.
}

Can it be possible something similar but using safestring? i mean eg. "safestring sendData(........){......}" Thanks

This code is used with an esp8266-01 and i want to understand if the failure of my system to run for days is due of String overflow.

[drmpf]

Perhaps the failure is due to String OR just problems with the underlying libraries, see Out-Of-Memory on ESP32 and ESP8266 – Add Periodic Automatic Reboots

However to convert to SafeString you need to pass a SafeString &result as an argument because SafeString prohibits the memory allocation needed to handle a return value. See the SafeString library tutorial. The section on Passing SafeStrings to methods as references and returning SafeString results

void sendData(SafeString& response , SafeString& command, const int timeout, boolean debug) {
    response = "";  //initialize a String variable named "response". we will use it later.
    Serial.print(command);   //send the AT command to the esp8266 (from ARDUINO to ESP8266).
    long int time = millis(); //get the operating time at this specific moment and save it inside the "time" variable.
    while( (time+timeout) > millis()) //excute only whitin 1 second.
    {      
      while(Serial.available())   //is there any response came from the ESP8266 and saved in the Arduino input buffer?
      {
        char c = Serial.read(); //if yes, read the next character from the input buffer and save it in the "response" String variable.
        response+=c; //append the next character to the response variabl. at the end we will get a string(array of characters) contains the response.
      }  
    }   
    if(debug)  //if the "debug" variable value is TRUE, print the response on the Serial monitor.
    {
      Serial.print(response);
    }    
    return;  //return the String response.
}

Then somewhere at the top of your code create the SafeString to hold the response and command

createSafeString(response,80);  // good for 80 response
createSafeString(command,80); // good for 80 char cmd

Now your real problem is outputing the errors since you are using Serial for the ESP AT coms. Two things you can do:- i) set up a SoftwareSerial to send the errors to SafeString::setOutput(softwareSerial) and connect that to your computer (via TTL-usb cable OR another UNO (softwareSerial in Serial out to your computer) ii) Turn on the UNO led on SafeString errors i.e.

void loop() {
    if (SafeString::errorDetected()) {
       digitalWrite(ledPin,HIGH);
    }
 // . . . 

[Attigliuzzo]

Thanks for your tricks and your library (especially the GPS example, i learned a lot).

I have already implemented a reboot of my esp8266 every 24 hours using AT commands, i hope this solve my issues but i'll read your links. My project uses an Arduino UNO but at home i test the code with a mega pro with its multiple serial ports to redirect the debug. Thanks again