Send a 4-byte Length Prefix over a Socket

See more Socket/SSL/TLS Examples

Demonstrates Socket.SendCount, which sends a four-byte length prefix in network byte order. This is typically used to tell the peer how many bytes follow.

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

success = 0

set socket = CreateObject("Chilkat.Socket")

'  Connect to the server using TLS.
bTls = 1
maxWaitMs = 5000
success = socket.Connect("example.com",5000,bTls,maxWaitMs)
If (success = 0) Then
    outFile.WriteLine(socket.LastErrorText)
    WScript.Quit
End If

'  Send a four-byte length prefix in network byte order.  A common framing pattern is to send the
'  number of bytes in a message before the message itself, so the peer knows exactly how many bytes
'  to read.
messageLength = 512
success = socket.SendCount(messageLength)
If (success = 0) Then
    outFile.WriteLine(socket.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine("Length prefix sent.")

outFile.Close