EthernetUDP.read()

Description

Reads UDP data from the specified buffer. If no arguments are given, it will return the next character in the buffer.

This function can only be successfully called after Udp.parsePacket().

Syntax


Udp.read();
Udp.read(packetBuffer, MaxSize);


Parameters

packetBuffer: buffer to hold incoming packets (char)
MaxSize: maximum size of the buffer (int)

Returns

char : returns the characters in the buffer

Example

#include <Ethernet.h>
#include <EthernetUdp.h>

// Enter an IP address for your controller below.
// The IP address will be dependent on your local network:
IPAddress ip(192, 168, 1, 177);

unsigned int localPort = 8888;      // local port to listen on

// An EthernetUDP instance to let us send and receive packets over UDP
EthernetUDP Udp;

char packetBuffer[UDP_TX_PACKET_MAX_SIZE]; //buffer to hold incoming packet,

void setup() {
  // start the Ethernet and UDP:
  Ethernet.begin(NULL,ip);
  Udp.begin(localPort);
}

void loop() {
  int packetSize = Udp.parsePacket();
  if(packetSize)
  {
    Serial.print("Received packet of size ");
    Serial.println(packetSize);
    Serial.print("From ");
    IPAddress remote = Udp.remoteIP();
    for (int i =0; i < 4; i++)
    {
      Serial.print(remote[i], DEC);
      if (i < 3)
      {
        Serial.print(".");
      }
    }
    Serial.print(", port ");
    Serial.println(Udp.remotePort());

    // read the packet into packetBufffer
    Udp.read(packetBuffer,UDP_TX_PACKET_MAX_SIZE);
    Serial.println("Contents:");
    Serial.println(packetBuffer);
  }
}

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The text of the 86Duino reference is a modification of the Arduino reference, and is licensed under a Creative Commons Attribution-ShareAlike 3.0 License. Code samples in the reference are released into the public domain.