parseInt() on WiFiClient stream returns a 0 in Arduino Uno R4

[v-c]

parseInt() returns zero when called on the WiFiClient stream. Here's the simplest example. Paste this into a new ESP32 example on www.wokwi.com, or use an actual ESP32 board, or any non Renesas Arduino board.

#include <WiFi.h>

#define SECRET_SSID "Wokwi-GUEST" /// CHANGEME when using a real board
#define SECRET_PASS ""                       /// CHANGEME when using a real board

WiFiClient client;
int t;
String s;

void setup() {
  Serial.begin(115200);
  while (!Serial) {
    ; // wait for serial port to connect. 
  }

}

void loop() {
 if(WiFi.status() != WL_CONNECTED){
    Serial.print("Attempting to connect to SSID: ");
    Serial.println(SECRET_SSID);
    while(WiFi.status() != WL_CONNECTED){
      WiFi.begin(SECRET_SSID, SECRET_PASS);
      Serial.print(".");
      delay(5000);     
    } 
    Serial.println("\nConnected.");
 } else {
  if (client.connect("httpbin.org", 80)) {
    Serial.println("connected to server");
    client.println("GET /ip HTTP/1.1");
    client.println("Host: httpbin.org");
    client.println("Connection: close");
    client.println();
    }

    t = client.parseInt();
    Serial.println(t,DEC);
    delay(5000);
 }
}

Now, paste the same thing in Arduino IDE that is programming a Arduino Uno R4 and see that it always returns 0.

Also refer to the Stream utility class' parseInt method documentation here: https://www.arduino.cc/reference/tr/language/functions/communication/stream/streamparseint/

It appears that the WifiClient here does not behave the way other communication streams on Arduino work.