Question

I’m expanding a VB6 application which communicates with small embedded systems to use the serial port (they currently use UDP broadcasts); and thus am trying to emulate UDP packets over serial.

Part of this includes a message length in the header, which is two bytes long.

How can I convert an integer in VB6 to two bytes ( byte(2) ) so that program written in C that picks up the message can cast it to a short integer?

Answer 1

The easiest way is to do this.

Private Type IntByte
    H As Byte
    L As Byte
End Type


Private Type IntType
    I As Integer
End Type

Public Sub Convert(ByVal I as Integer, ByRef H as Byte, ByRef L as Byte)

  Dim TempIT As IntType
  Dim TempIB As IntByte

 TempIT.I = I

  LSet TempIB = TempIT

  H = TempIT.H
  L = TempIT.L

End Sub

You can use this technique to break up other data types into bytes.

Private Type LongByte
    H1 As Byte
    H2 As Byte
    L1 As Byte
    L2 As Byte
End Type

Private Type DblByte
    H1 As Byte
    H2 As Byte
    H3 As Byte
    H4 As Byte
    L1 As Byte
    L2 As Byte
    L3 As Byte
    L4 As Byte
End Type