WebTelnetSyncCommand Function


Notes a Telnet command to be verified as received on next sending operation in a Telnet connection. This asynchronous function helps building more robust scripts because some Telnet servers mix Telnet command sequences with regular output data. The received data itself will be prepended to data in the order it was received in the next subsequently received function call.

Include file



WebTelnetSyncCommand(    in hWeb : number,
    in iCmd : number,
    in iOpt : number optional ) : boolean;

Return value

  • true if the operation was successful

  • false otherwise

Parameter Description
hWeb Valid handle to a Web connection created by WebTcpipConnect and set to Telnet mode using WebTcpipSetTelnetMode. The connection must be in “Sync-Mode” (set option TELNET_MODEOPT_SYNC).
iCmd Telnet command to be received from the server (optional). If omitted or set -1 then no verification will be performed. See constants in WebTelnetSendCommand for valid values.
iOpt Telnet option for WILL/WONT/DO/DONT and SB Telnet commands (optional). See constants in WebTelnetSendCommand for valid values. If omitted or set to -1 no verification will be performed.


  transaction TInit
    StrSetHostCP(28591); // 28591 (ISO 8859-1 Latin I)
  end TInit;

  transaction   TMain
    hWeb0     : number;
    sBuffer   : string;
    sBoundary : string;
    nOption   : number;
    WebTcpipConnect(hWeb0, "My.TelnetHost.IP", WEB_PORT_TELNET);
    WebTcpipSetTelnetMode(hWeb0, TERMINAL_TYPE_ANSI, 80, 24, true,
    WebTelnetSetTerminalConfigString(hWeb0, "AutoWrap=false 8Bit=false Tab=9*");

    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_TerminalType);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_NegotiateWindowSize);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_RemoteFlowControl);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_SendLocation);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_WILL, TELNET_OPT_Echo);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_WILL, TELNET_OPT_SuppressGoAhead);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_TerminalSpeed);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_XDisplayLocation);

    // commands above are verified here
    WebTelnetSendCommand(hWeb0, TELNET_CMD_WILL, TELNET_OPT_TerminalType);
    WebTelnetSendCommand(hWeb0, TELNET_CMD_WILL, TELNET_OPT_NegotiateWindowSize);
    WebTelnetSendSubNegotiation(hWeb0, TELNET_OPT_NegotiateWindowSize, "\h00500018"); //•P••
    WebTelnetSendCommand(hWeb0, TELNET_CMD_WONT, TELNET_OPT_RemoteFlowControl);
    WebTelnetSendCommand(hWeb0, TELNET_CMD_WONT, TELNET_OPT_SendLocation);
    WebTelnetSendCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_Echo);
    WebTelnetSendCommand(hWeb0, TELNET_CMD_DO, TELNET_OPT_SuppressGoAhead);
    WebTelnetSendCommand(hWeb0, TELNET_CMD_WONT, TELNET_OPT_TerminalSpeed);
    WebTelnetSendCommand(hWeb0, TELNET_CMD_WONT, TELNET_OPT_XDisplayLocation);
    WebTelnetSyncSubNegotiation(hWeb0, TELNET_OPT_TerminalType);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DONT, TELNET_OPT_RemoteFlowControl);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DONT, TELNET_OPT_SendLocation);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DONT, TELNET_OPT_TerminalSpeed);
    WebTelnetSyncCommand(hWeb0, TELNET_CMD_DONT, TELNET_OPT_XDisplayLocation);
    // sync commands above are verified here
    WebTelnetSendTerminalType(hWeb0, "vt100");
    // sync commands above are received here
    WebTcpipRecvClose(hWeb0, NULL);
  end TMain;