VB.NET

Socket Send/Receive 16-bit Integers

Demonstrates sending and receiving 16-bit integers over a socket connection using either big-endian or little-endian byte ordering. VB.NET

Dim success As Boolean = False

' This example requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

Dim sock As New Chilkat.Socket

' --------------------------------------------------------------------
' This example uses the public TCP echo service at https://tcpbin.com/
' --------------------------------------------------------------------

Dim useTls As Boolean = False
Dim port As Integer = 4242
Dim maxWaitMs As Integer = 5000
success = sock.Connect("tcpbin.com",port,useTls,maxWaitMs)
If (success = False) Then
    Debug.WriteLine(sock.LastErrorText)
    Exit Sub
End If


' Wait a max of 2 seconds for a response..
sock.MaxReadIdleMs = 2000

' Send a 16-bit integer using big-endian byte ordering (also called network byte order)
' 12022 decimal = 2EF6 hex
Dim value As Integer = 12022
Dim bigEndian As Boolean = True
sock.SendInt16(value,bigEndian)
' Send it again, because we'll read it two different ways..
sock.SendInt16(value,bigEndian)

' The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
sock.SendByte(10)

' Let's see hex values of the 2 bytes sent in network byte order (big-endian)
' (The echo server sends back exactly the bytes received.)
Dim hexStr As String = sock.ReceiveNBytesENC(2,"hex")

' In the big-ending byte order, the byte order is most significant byte to least significant,
' therefore we should see the bytes in the order 0x2E 0xF6.
Debug.WriteLine("Expecting big-endian 2EF6")
Debug.WriteLine(hexStr)

' Let's read directly to an integer..
success = sock.ReceiveInt16(bigEndian,True)
Debug.WriteLine("Expecting 12022")
Debug.WriteLine("Received: " & sock.ReceivedInt)

' Consume the LF that gets echoed back..
sock.ReceiveByte(True)

' --------------------------------------------------------------------
' Let's do the same thing, but with little-endian byte ordering.

Debug.WriteLine("----")

' 12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
value = 12022
bigEndian = False
sock.SendInt16(value,bigEndian)
sock.SendInt16(value,bigEndian)
sock.SendByte(10)

hexStr = sock.ReceiveNBytesENC(2,"hex")

Debug.WriteLine("Expecting little-endian F62E")
Debug.WriteLine(hexStr)

success = sock.ReceiveInt16(bigEndian,True)
Debug.WriteLine("Expecting 12022")
Debug.WriteLine("Received: " & sock.ReceivedInt)

' Consume the LF that gets echoed back..
sock.ReceiveByte(True)

sock.Close(1000)

' Output:

' Expecting big-endian 2EF6
' 2EF6
' Expecting 12022
' Received: 12022
' ----
' Expecting little-endian F62E
' F62E
' Expecting 12022
' Received: 12022