UDPSocketClose

Example #1

' A simple UDP client example sending data to another device and receiving data back

'UDP Variables
Const RecvBufferSize = 200

Public SockID As Long
Public bytesWritten As Long

Public bytesReceived As Long

Public recvDatagramStr As String * RecvBufferSize 'Leave space for null terminator
Public remoteIP As String * 100
Public remotePort As Long
Public recvTimeouts As Long 'increment this if we time out waiting for a response

Public PTemp, Batt_volt

Dim inputSize As Long
Dim recvDatagramBytes(RecvBufferSize) As UINT1 'We are receiving raw bytes back, so use UINT1

DataTable (Test,1,-1)
  DataInterval (0,15,Sec,10)
  Minimum (1,Batt_volt,FP2,False,False)
  Sample (1,PTemp,FP2)
EndTable

'Main Program 
BeginProg
  Scan (1,Sec,0,0)
    PanelTemp (PTemp,15000)
    Battery (Batt_volt)

    CallTable Test
  NextScan

  SlowSequence

  Scan(30,Sec,0,0)

    UDPSocketOpen(SockID, 0, 3) 'We are a client, so get an ephemeral port
    If (SockID >= 0) Then
      'Socket successfully opened 

      'If you were trying to send to a remote host with a domain name, you would use the DNSQuery instruction here to get the IP associated
      ' with that domain
      'example:
      '
      ' Public ipAddr As String * 100
      ' DNSQuery(Ret, ipAddr, "domain.com")
      ' If Ret = 0 Then
      ' ' We successfully resolved the domain to an IP, put rest of code in here

      UDPSocketSend(bytesWritten,SockID,"10.34.10.12", 40000,"Bytes sent over UDP",19) 'size 19 to not include null character
      If (bytesWritten >= 0) Then
      'Successfully wrote out the message, now get a response
        UDPSocketRecv(bytesReceived,SockID,recvDatagramBytes,0,remoteIP,remotePort, 500) 'Wait half a second for a response
        If (bytesReceived > 0) Then
        'We got a response with a non-zero payload size
          If (bytesReceived >= RecvBufferSize) Then
            inputSize = RecvBufferSize
            'They sent us more bytes than our buffer can hold, so the input was truncated to the size of the buffer.
            'Since this is just binary data, we need to add the null terminator ourselves before copying into our string. Since the buffer
            'is full, we'll overwrite the last byte of data with a null terminator
            recvDatagramBytes(RecvBufferSize) = &h00
          Else
            inputSize = bytesReceived + 1 'Add 1 for null terminator we are going to add
            'We know that we have space in the buffer to add a null terminator without overwriting any data
            recvDatagramBytes(inputSize) = &h00
          EndIf

          'Copy into string variable (this code makes the assumption that all of these bytes are printable characters, which is not an
          'assumption actual application should make)
          MoveBytes(recvDatagramStr, 0, recvDatagramBytes, 0, inputSize)
        ElseIf (bytesReceived = -1) Then
          'We timed out waiting for a response
          recvTimeouts += 1
        EndIf
      EndIf

      UDPSocketClose(SockID) 'If a socket is successfully opened, it will stay open until it is closed
    EndIf
  NextScan
  EndSequence
EndProg