String(negativeInteger, HEX) doesn't return the same thing than with an Arduino UNO.

[pierrepoulpe]

Basic Infos

Hardware

Hardware: NodeMCU ESP-12E
Core Version: 2.3.0

Description

String(negativeInteger, HEX) doesn't return the same thing than with an Arduino UNO.

Settings in IDE

Module: NodeMCU 1.0
Flash Size: 4MB/3MB
CPU Frequency: 80Mhz
Upload Using: SERIAL
Reset Method: nodemcu

Sketch

long a;

void setup() {
  // put your setup code here, to run once:
  a = -100;
  delay(500);
  Serial.begin(9600);
  Serial.println(String(a,HEX));
  

}

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

}

Serial Output

-64

Exact same code, uploaded to UNO

ffffff9c

Strange, isn't it? I supposed String library was platform independant... I was wrong.

Uno version sounds better to me....

[devyte]

@pierrepoulpe is this still an issue in latest git? I think the correct output should be what you get for the UNO.

[earlephilhower]

This is a bug.

Our ltoa doesn't behave correctly for negative, non base10 #s. It should be safe to replace the shim functions in core_esp8266_noniso.c with calls to itoa and utoa since long and int are the same size.

[earlephilhower]

Fixed with #5625