Hello everyone. I'm an unix guy trying to write a winsock client in VB
to existing server that is running on UNIX. This unix server listens on
a port. It is expecting messages in the form of structures. The
structure itself contains different datatypes. I created a recordset on
VB side. I connected to unix server using connect of winsock control. I
filled the record set with proper data, and now I want to send it to
unix machine. The senddata method of winsock is expecting the data in
byte order form. How do I make this structure
byte ordered? What is this byte order anyway? I'll be so greatful for
your help.

Surya

The first thing you'll need is an apiu call that copies your structure in
VB to a byte array. The second thing to watch is byte ordering (A long is 4
bytes only VB stores them the opposite way to unix). Here is some sample
code that may help you.

Private Const BufferSize = 1024
Private Const TwoLongs = 8

Private Type SocketPacket
    PacketSize As Long
    TextSize As Long
    PacketBuffer(1 To BufferSize) As Byte
End Type

Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
    (hpvdest As Any, hpvSource As Any, ByVal cbCopy As Long)

   Dim NewPacket As SocketPacket
    Dim TempString As String
    Dim LongReverse(1 To 4) As Byte
    Dim StringLength As Integer
    Dim PacketBuffer() As Byte

    TempString = "1234567890" + Chr$(0)
    StringLength = Len(TempString)

    NewPacket.PacketSize = BufferSize + TwoLongs
    NewPacket.TextSize = StringLength

    ReDim PacketBuffer(NewPacket.PacketSize - 1)

    Call CopyMemory(NewPacket.PacketBuffer(1), ByVal TempString,
(Len(TempString) + 1))
    Call CopyMemory(PacketBuffer(0), NewPacket, Len(NewPacket))

    LongReverse(1) = PacketBuffer(3)
    LongReverse(2) = PacketBuffer(2)
    LongReverse(3) = PacketBuffer(1)
    LongReverse(4) = PacketBuffer(0)
    PacketBuffer(0) = LongReverse(1)
    PacketBuffer(1) = LongReverse(2)
    PacketBuffer(2) = LongReverse(3)
    PacketBuffer(3) = LongReverse(4)
    LongReverse(1) = PacketBuffer(7)
    LongReverse(2) = PacketBuffer(6)
    LongReverse(3) = PacketBuffer(5)
    LongReverse(4) = PacketBuffer(4)
    PacketBuffer(4) = LongReverse(1)
    PacketBuffer(5) = LongReverse(2)
    PacketBuffer(6) = LongReverse(3)
    PacketBuffer(7) = LongReverse(4)

    Winsock1.SendData PacketBuffer