CODEWITHSUNDEEP
arduinoesp32
Nikolay
Nikolay

Reputation: 245

Is there a reason not to print uint64_t directly?

I am looking into printing out the MAC address of an ESP32 board. The Arduino Examples define it by the following:

uint64_t chipid=ESP.getEfuseMac();//The chip ID is essentially its MAC address(length: 6 bytes).
Serial.printf("ESP32 Chip ID = %04X",(uint16_t)(chipid>>32));//print High 2 bytes
Serial.printf("%08X\n",(uint32_t)chipid);//print Low 4bytes.

However, I found the following way to do it: 

  uint64_t chipId = ESP.getEfuseMac();
  Serial.printf("%" PRIx64 "\n", chipId);

The second way is obviously more verbose, however, while looking online, I never found such an example with the Arduino boards. Is there a memory issue that way and if so - what?

Upvotes: 2

Views: 1988

Answers (2)

Drowning_Ophelia
Drowning_Ophelia

Reputation: 31

If anyone's interested have a working header and source files that supports 64-bit int and long double printing natively. The code simply overloads the print() and println() functions to include these types. You can down the files here: https://github.com/Michael-Brodsky/PG/tree/main/hardware/avr

You'll need to replace the equivalent files supplied with the Arduino IDE (avr-libc), so I recommend making backups.

Upvotes: 0

Johannes Overmann
Johannes Overmann

Reputation: 5161

64-bit printf() support was added end of 2016 (I think) and the example seems to predate that. The PRIx64 is the correct way to print a 64-bit number.

See also https://github.com/espressif/esp-idf/issues/52

Upvotes: 3

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