Overlapped.hEvent := CreateEvent(nil, True, False, nil) Nil, OPEN_EXISTING, FILE_FLAG_NO_BUFFERING or FILE_FLAG_OVERLAPPED, 0) įillChar(Overlapped, SizeOf(TOverlapped), 0)

Result := CreateFile(PChar(ComName), GENERIC_READ or GENERIC_WRITE, 0, The following function returns a handle to the specified COM number and initializes the Overlapped record:Ĭode: Select all function OpenComPort(ComNum: Integer var Overlapped: TOverlapped): Integer The other members of this record should be zero for communication devices. Then, to read (or write) data you have to defined a TOverlapped record and assign an event handle to its hEvent member. You have to add the FILE_FLAG_OVERLAPPED flag to the flags of CreateFile procedure. seems really nice, but how to respond to the incoming characters immediately and empty the input buffer ? And still not being in a loop and waiting for event, which might not happen at all or occur once in several minutes or so. This solution with having a handle to COMx and making different system calls like GetCommState, WaitCommEvent etc. I would like to stress that I don't want to use some third party components. When it comes to receiving characters, almost everybody uses SetCommMask to set for EV_RXCHAR event, then uses WaitCommEvent to respond to this particular event and read the buffer.īut does it mean that I must use some kind of a loop and wait for the event, thus risking to stay in a loop forever and don't do anything else useful? How can I solve this problem more elegantly, like having an event handler for my COMx handle to respond to? I know that one can write an EventHandle for an object, but an event handler for a virtual file handler referring to COMx ? Everybody uses handles with CreateFile (COMx.) etc, then uses ReadFile, WriteFile. I have found many source codes all over the network about how to access the serial port in Delphi.

Read/write to serial port various types of data: string, binary, byte array of VARIANTS (for ASP), etcĪbility to set up serial port settings within a single string (9600-N-8-1)Įasily get the list of all available ports in a system and open anyĮxamples for Microsoft VC++.

You can easily receive all the details about the port your application works with: controller type, supported protocols, adjustable settings, etc.Īny number of ports can be controlled at the same time Flexible set of ActiveX methods and properties for advanced control of all serial portsįull signal lines support (DTR/DSR/RTS/CTS/Ring)Įxtensive serial port configuration management (Baudrate, Databits, Parity, Flow Control, StopBits)Ībility to set up control characters and timeouts for serial port

Serial Port In Delphi