itoa giving wrong result in IDE 1.6.5r5

Development Tools IDE 1.x
1

Hi

I have updated my IDE from 1.0.6 to 1.6.5r5. Now i get a wrong filename when using itoa.
I have attached a sample code that produces the error on a MEGA2560
Time was set to 2016/4/2 06:09:32

Correct output from IDE 1.0.6

2016
2016
4
LT2016

From IDE 1.6.5r5 the the digit "4" are added.

2016
20164
4
LT20164

and if time are set to 2016/2/24 06:08 the out put are

2016
20162
2
LT20162

I think it is a kind of buffer overrun because if I remove
itoa(yeaat,charbufferyeaat,10);
itoa(monat,charbuffermonat,10);
The out put on IDE 1.6.5.r5 are

2016
2016
4

#include <RTClib.h>
#include <Wire.h>
//Set up the RTC, pint A8 and A9 used for power
RTC_DS1307 RTC;

DateTime  now;

void setup() {
  pinMode (A8,OUTPUT); // Power for RTC
digitalWrite(A8,LOW); // Power for RTC
pinMode (A9,OUTPUT); // Power for RTC
digitalWrite(A9,HIGH); // Power for RTC
  RTC.begin();
  Wire.begin();
Serial.begin(115200);   //enable serial data print 
  now = RTC.now(); 
  // put your setup code here, to run once:
   int  yeaat,monat;
   char charbufferyeaat[4],charbuffermonat[2];
      char filename2[13]="LT";  //file prefix
      yeaat = now.year(); // convert byte to int 
      monat = now.month();  // convert byte to int
      itoa(yeaat,charbufferyeaat,10);
      itoa(monat,charbuffermonat,10);

Serial.println(yeaat);
Serial.println(charbufferyeaat);
Serial.println(monat);
strcat(filename2, charbufferyeaat); //append the year to the prefix
 Serial.println(filename2);
}

void loop() {
  // put your main code here, to run repeatedly:

}
2

Yes, it is a buffer overrun, because you have supplied buffers that are too small for the data you're stuffing into them.

You forgot about the null terminator at the end, so the strings are unterminated, so you're getting the next bytes in memory until it hits a null. You should make each array 7 bytes long (1 for terminator, 5 for the value, 1 for the - sign), so that no matter what you pass itoa, even blatantly bogus data, it won't overrun.

3

I knew it, it always the NULL....
I guess it doesn't help to say i stole the code on the net....

Thanks.
I am impressed by the quick replies, no matter how dumb question asked.