[avr-libc-dev] realloc shrinking corrupts last two bytes of shrunk chunk

[Francesco Potortì]

This is a demo "sketch" written for Arduino:

/*
 * Output should be:
 *  0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55
 *  0x55 0x55 0x55 0x55 0x55 0x55
 *
 * Output is:
 *  0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55 0x55
 *  0x55 0x55 0x55 0x55 0x6 0x0
 *
 */

void setup()
{
  char hexstring[3];
  Serial.begin(115200);

  int len = 14;

  byte *ptr = (byte *)malloc(len);
  memset(ptr, 0x55, len);
  for (byte i=0; i<len; ++i)
    {
      Serial.print(" 0x");
      Serial.print(itoa(ptr[i], hexstring, 16));
    }
  Serial.println("");

  ptr = (byte *)realloc(ptr, len-8);
  for (byte i=0; i<len-8; ++i)
    {
      Serial.print(" 0x");
      Serial.print(itoa(ptr[i], hexstring, 16));
    }
  Serial.println("");
}

void loop()
{
}