Circularbuffer vs EEPROM.read/write

[Francois1976]

Hi, I would like to restore the value of my buffer during my arduino bootup. Is there a way to do it?

My buffer is define like that and work well:
CircularBuffer<int, 24> buffer;

I backup like this:

   EEPROM.update(0, buffer[0]);
   EEPROM.update(1, buffer[1]);
   EEPROM.update(2, buffer[2]);

I try to restore like that on the SETUP part of my program

  buffer[0]=EEPROM.read(0);
  buffer[1]=EEPROM.read(1);
  buffer[2]=EEPROM.read(2);

but I cannot I received the following error during the compile:

"lvalue required as left operand of assignment"

I also tryed some other way to restore but never find the good one....

So for my bad english ;o)

Thanks!

[rlogiacco]

The message is quite obvious, but to put it simple, you are trying to treat the buffer as if it was an array and use the [] to identify an item in the buffer and perform an assignment: that is not going to work.

The [] operator can be used to read data from the buffer, not to perform assignments, that is why you find the [] operator listed in the retrieve data section of the readme but not in the store data.

What you can do is replace your

// this cannot work because the left operand is not assignable (lvalue)
buffer[0]=EEPROM.read(0);
buffer[1]=EEPROM.read(1);
buffer[2]=EEPROM.read(2);

with

// this works because we are appending to the buffer
buffer.push(EEPROM.read(0));
buffer.push(EEPROM.read(1));
buffer.push(EEPROM.read(2));

or even better with

// read all the 24 positions and restore the buffer contents
for (uint8_t i = 0; i < 24; i++) {
  buffer.push(EEPROM.read(i));
}