DataFlex

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. DataFlex

Use ChilkatAx-win32.pkg

Procedure Test
    Boolean iSuccess
    Handle hoSock
    Boolean iUseTls
    Integer iPort
    Integer iMaxWaitMs
    Integer iValue
    Boolean iBigEndian
    String sHexStr
    String sTemp1
    Integer iTemp1

    Move False To iSuccess

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

    Get Create (RefClass(cComChilkatSocket)) To hoSock
    If (Not(IsComObjectCreated(hoSock))) Begin
        Send CreateComObject of hoSock
    End

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

    Move False To iUseTls
    Move 4242 To iPort
    Move 5000 To iMaxWaitMs
    Get ComConnect Of hoSock "tcpbin.com" iPort iUseTls iMaxWaitMs To iSuccess
    If (iSuccess = False) Begin
        Get ComLastErrorText Of hoSock To sTemp1
        Showln sTemp1
        Procedure_Return
    End

    // Wait a max of 2 seconds for a response..
    Set ComMaxReadIdleMs Of hoSock To 2000

    // Send a 16-bit integer using big-endian byte ordering (also called network byte order)
    // 12022 decimal = 2EF6 hex
    Move 12022 To iValue
    Move True To iBigEndian
    Get ComSendInt16 Of hoSock iValue iBigEndian To iSuccess
    // Send it again, because we'll read it two different ways..
    Get ComSendInt16 Of hoSock iValue iBigEndian To iSuccess

    // The tcpbin.com echo server only echoes after receiving an LF (linefeed char)
    Get ComSendByte Of hoSock 10 To iSuccess

    // 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.)
    Get ComReceiveNBytesENC Of hoSock 2 "hex" To sHexStr

    // 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.
    Showln "Expecting big-endian 2EF6"
    Showln sHexStr

    // Let's read directly to an integer..
    Get ComReceiveInt16 Of hoSock iBigEndian True To iSuccess
    Showln "Expecting 12022"
    Get ComReceivedInt Of hoSock To iTemp1
    Showln "Received: " iTemp1

    // Consume the LF that gets echoed back..
    Get ComReceiveByte Of hoSock True To iSuccess

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

    Showln "----"

    // 12022 decimal = 2EF6 hex, but little-endian byte ordering will send the bytes in the order 0xF6 0x2E
    Move 12022 To iValue
    Move False To iBigEndian
    Get ComSendInt16 Of hoSock iValue iBigEndian To iSuccess
    Get ComSendInt16 Of hoSock iValue iBigEndian To iSuccess
    Get ComSendByte Of hoSock 10 To iSuccess

    Get ComReceiveNBytesENC Of hoSock 2 "hex" To sHexStr

    Showln "Expecting little-endian F62E"
    Showln sHexStr

    Get ComReceiveInt16 Of hoSock iBigEndian True To iSuccess
    Showln "Expecting 12022"
    Get ComReceivedInt Of hoSock To iTemp1
    Showln "Received: " iTemp1

    // Consume the LF that gets echoed back..
    Get ComReceiveByte Of hoSock True To iSuccess

    Get ComClose Of hoSock 1000 To iSuccess

    // Output:

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


End_Procedure