Using Delphi 7 I am reading from a serial port.
The read is always preceded by a write which triggers the h/w to measure from a sensor and write something for me to read (and there is always something to read).
I have two possibilities: manually enter a command and click a button to write that to the serial port (read model or f/w version, etc) or click a button to loop reading measurements until a stop button is pressed. These both use the same internal functions, so the code looks something like this:
WriteSerial('?model');
SerialData := ReadSerial(); // returns string
WriteSerial('?fw');
SerialData := ReadSerial();
and
while stopButtonNotPressed do
begin
WriteSerial('?data');
SerialData := ReadSerial();
Memo1.Lines.Add(SerialData );
end;
The first variant (manually entering a command & pressing a button) is always successful, no matter how quickly or slowly I enter commands (hold down button for repeat), where are the second goes
pass
fail
pass
pass
fail
pass
pass
fail
... add infinitum
adding calls to sleep produces nothing, but trying to debug, I found that if I add a modal dialog box MsgDialog, 'Please close this dialog...', mtInfo, [mrOK]); to the loop, then it no longer fails.
Now, it doesn't look like timing (else surely adding Sleep(2000); to the loop would make it pass & does not, so why does pressing a button on the main form or the modal dialog cause it to succeed?
Btw, the h/w user guide says nothing of CTS / RTS, and the sole code example provide also does not.
Note: if I manually enter ?data repeatedly it never fails ...
Any ideas?
Your serial devices need time to react, so obviously you need a break for the device to catch up. When you use the keyboard to push the button you're providing the brake it needs because the keyboard repeat isn't all that fast.
As you say Sleep(2000) should provide plenty of "break", but there are two other potential problems you'll need to take care of:
Serial communication isn't necessary buffered: Sleep(2000) might be too long!
The serial library you're using might be using windows messages to process incoming bytes. Sleep() inhibits the message pump, so no more messages flow towords your application
Try "sleeping" using something like this:
procedure BusyWait(ms: Cardinal);
var StopAt: TDateTime;
begin
StopAt := Now + EncodeTime(0, 0, ms div 1000, ms mod 1000);
while StopAt > Now do
begin
Application.ProcessMessages;
Sleep(50); // per Michał Niklas's suggestion, to keep the CPU from reaching 100%
end;
end;
This routine will wait, but it'll keep the message pump going, allowing your serial library to receive messages. If that's the problem...
Maybe adding Application.ProcessMessages() before Sleep() will help.
Related
After launching osk.exe with ShellExecuteEx() I would like to position the keyboard window relative to the data-entry fields, so that it doesn't cover them.
How do I set the window position for the osk before calling it?
Also, how can I have the application hide the osk when I am finished?
You can use FindWindow using the window class "OSKMainClass" to get the window handle, and then SetWindowPos on that handle to position it to the coordinates you want. (You may need to use the control's ClientToScreen method to convert to the proper coordinates, but I'll let you figure that part out.)
// Off the top of my head - not at a machine that has a Delphi compiler at
// the moment.
var
OSKWnd: HWnd;
begin
OSKWnd := FindWindow(PChar('OSKMainClass'), nil);
if OSKWnd <> 0 then
begin
SetWindowPos(OSKWnd,
HWND_BOTTOM,
NewPos.Left,
NewPos.Top,
NewPos.Width,
NewPos.Height,
0);
end;
end;
Code taken in part from a CodeProject article related to the same topic. I got the window class using AutoHotKey's Window Spy utility.
Notes:
Remy Lebeau points out in a comment that you should make sure to use CreateProcess() or ShellExecuteEx() so that you get back a process handle that can then be passed to WaitForInputIdle() before calling FindWindow(). Otherwise the call to FindWindow() may happen before OSK creates the window.
mghie points out in a comment that the only way he could get this to work was by running the app as Administrator; otherwise the call to SetWindowPos() resulted in an "Access Denied (5)".
I can,t move the window as mentioned above.
Using Win32 commands, SetWindow or MoveWindow not worked for on screen keyboard.
Its worked only while running exe in admin privilege.
I think its not a good solution.
I found another solution.
Please go through this.
After trying using registry values its worked well i can move on screen keyboard in my application
try
{
RegistryKey myKey = Registry.CurrentUser.OpenSubKey(#"SOFTWARE\Microsoft\Osk", true);
myKey.SetValue("WindowLeft", oskLeft, RegistryValueKind.DWord);
myKey.SetValue("WindowTop", oskTop, RegistryValueKind.DWord);
}
catch
{
//Log the error
}
I am working with application in delphi. I need to use MIDIYOKE to send output from my application to another application. The second application is Virtual piano keyboard.
I installed all the packages and got MIDI components in the delphi.
I tried using MidiOutputPort1 and MidiInput1 components.
I tried playing one MIDI.The code is as follows:
procedure TForm3.Button1Click(Sender: TObject);
var
outputPort : TMidiOutputPort;
begin
outputPort := TMidiOutputPort.Create (Nil);
try
outputPort.PortId := -1;
outputPort.Active := True;
outputPort.PatchChange(0, 127, 0); // Gunshot
outputPort.NoteOn (1, 20, 127); // Play note at full volume
Sleep (1000);
outputPort.NoteOff (0, 60, 0);
finally
outputPort.Free
end
end;
I wanted to estalish connection between my application and Virtual piano keyboard.How to use MidiOutputPort1 and MidiInput1 for the connection between the two.
If both applications support MIDI sync you can use MIDI syncing. In that case MIDIYOKE is the master and Vpk is the slave. Syncing is handled by the following commands:
mc_MIDI_Timing_Clock = $F8;
mc_MIDI_Start = $FA;
mc_MIDI_Continue = $FB;
mc_MIDI_Stop = $FC;
I used it in the far past, so my knowledge is a bit rusty. What I can gather from my code is that it works as follows: Set the slave in the slave/sync receive/whatever it's called mode. Next send $FA to the channel of your choice. Some (not all) slaves require you to listen to specific channels.
At each clock tick send $F8 first. Next send the messages, preceded by the $FB message (both data bytes zero). When you're ready send $FC.
I think you should put the port number of one of your yoke ports in the portid property.
To know which id to use, you'll have to enumerate the available ports, because the id's can change if you add hardware, or if you change your midi yoke configuration.
Therefore, to remember which ports were chosen by the user, you need to store the device name, and hope that the user doesn't rename its devices :)
Let me know if this helps you enough to be able to continue your work; otherwise i'll dig up some old code that does what you're attempting to do.
I am a long time Delphi dev and in the past I use a third party tool for logging and debugging while developing (called Smart Inspect) however now that I've upgraded to Delphi XE I want to try and use the IDE for debugging.
My question is, given a function like
procedure MyFunction;
var
str : string;
begin
str := 'Foo';
//Debug, show value of str?
str := AnotherFunction(str);
//Debug, show value of str?
end;
how can I debug and get the value of str, without doing stupid things like
showmessage(str);
if there is a video somewhere (or article) then I am more than happy to read.
Is there a way to watch/output the value of variables.
If you want to use the IDE Debugger only, then do the following:
put a breakpoint somewhere
right click on the breakpointr circle and choose "Breakpoint Properties ..."
press "Advanced" button to show more options
uncheck "Break" checkbox
then use "Log message" and "Eval expression" edit boxes to enter trace values
Such messages will be send to "Event Log" debugger pane. Right click on the pane and choose "Properties". There you can filter ("Messages") / hilight ("Colors") the trace messages as you whish.
Well, Delphi XE comes with CodeSite logging, but I get the feeling you're talking about the debugger itself.
If you place a breakpoint in a routine, it will break to the debugger when it hits it. From there, you've got a Local Variables pane and a Watches pane along the left side of the IDE. Local Variables will show the value of all locals, and Watches lets you set up expressions whose value it will keep track of.
You can also get something similar to a watch, but with more detailed information (especially for structured types such as objects) by using Inspect (Alt-F5). Also, the Evaluate/Modify (Ctrl-F7) will allow you to type in expressions and evaluate them. It's not quite as detailed as Inspect, but it gives you a lot more flexibility.
If you familiarize yourself with these tools, you'll find debugging much easier.
1) You can use OutputDebugString Function to output string to debug window
2) You can use CodeSite Express. I recommend video from CodeRage 5 as a starting point for using CodeSite
Other answers are all correct.
My personal favorite technique (same as the answer by da-soft) is to create a breakpoint, that logs a message to the event log, containing a value that I want logged, and does not actually "break" (that is, execution continues without you hitting the Run icon). Then every time that line of code is reached, I get my message, and my values in the log. Since I can go back and read the history, as well as see the current values, I find this more useful than merely using the debugger watch window.
But since Delphi XE includes CodeSite, you can go far beyond what expression evaluation in breakpoints does for you. Code Site however requires that you modify your code to add some logging. But it's much better than a message box.
You can also use OutputDebugString(PChar(s)) to output any string to the debugger. Since this can contain whatever you want, it's a very nice way to debug but not show stuff to the end user.
In many of my applications, I have a special trace buffer, which is circular (that is, it keeps only the last 500 or so lines). When ever I see a problem, not only do I get a stack traceback, I also save that in-memory trace log, so I have some history on what was going on just before my problem.
You can also check out the Log 4 Delphi project.
I prefer debugger hints. After breaking to the debugger move your mouse to the "str" anywhere in your code and you will see its current value. Also you can highlight some statement by a mouse and evaluate it. For example highlight "AnotherFunction(str)" and place your mouse over it.
Nothing wrong with any of the other answers but I just wanted to add these useful functions.
procedure DebugString ( const s : string ) ; overload ;
begin
{$IFDEF DEBUG}
OutputDebugString ( PChar ( s ) ) ;
{$ENDIF}
end ;
procedure DebugString ( const s : string ; args : array of const ) ; overload ;
begin
{$IFDEF DEBUG}
OutputDebugString ( PChar ( Format ( s , args ) ) ) ;
{$ENDIF}
end ;
It should not be possible to run multiple instances of my application. Therefore the project source contains:
CreateMutex (nil, False, PChar (ID));
if (GetLastError = ERROR_ALREADY_EXISTS) then
Halt;
Now I want to restart my application programmatically. The usual way would be:
AppName := PChar(Application.ExeName) ;
ShellExecute(Handle,'open', AppName, nil, nil, SW_SHOWNORMAL) ;
Application.Terminate;
But this won't work in my case because of the mutex. Even if I release the mutex before starting the second instace it won't work because shutdown takes some time and two instance cannot run in parallel (because of common resources and other effects).
Is there a way to restart an application with such characteristics? (If possible without an additional executable)
Thanks in advance.
Perhaps you should think outside the box. Instead of futzing with the mutex / instance logic, you could simply create another executable that waits for your app to close then starts it again. As an added bonus, you can later use this mechanism to, for example, update some of your main app's binaries. It's also much easier to run it elevated instead of maintaining different integrity levels inside the same app, etc.
Why can't you just release the mutex before attempting to restart? If by some chance another instance gets going before the one you explicitly invoke with the restart that doesn't matter, you'll still have your app up and running again with whatever changes effected that required the restart. I don't think you need any of the complexity of the other solutions.
Include in your ShellExecute some parameter, for example, /WaitForShutDown and create one more mutex. In your program, before the initialization, for example, in its .dpr file, insert something like:
if (Pos('/WaitForShutDown', CmdLine) <> 0) then
WaitForSingleObject(ShutDownMutexHandle, INFINITE);
Also, in your program, after all the finalizations and releasing your common resources, include something like
ReleaseMutex(ShutDownMutexHandle);
EDIT...
OK. Now I belive that I know where is your problem...
You have problems with program units finalization!
Try to add at program section as first unit my bottom RestartMutex unit.
program MyProgramName;
uses
Mutex,
Forms,
...
;
unit RestartMutex;
interface
var
Restart: boolean = false;
implementation
uses
windows,
ShellApi;
var
MutexHandle: cardinal;
AppName: PChar;
const
ID = 'MyProgram';
initialization
MutexHandle := CreateMutex (nil, False, PChar (ID));
if (GetLastError = ERROR_ALREADY_EXISTS) then
Halt;
finalization
ReleaseMutex(MutexHandle);
if Restart then
begin
AppName := PChar('MyProgramName.exe') ;
ShellExecute(0,'open', AppName, nil, nil, SW_SHOWNORMAL) ;
end:
end.
When you want to restart application just set variable Restart to true and than terminate an application.
So, because is RestartMutex added as first in program section, this will couse that finalisation of unit RestartMutex will hepped nearly at the end of closing an application and all other units will do finalization before unit RestartMutex, that mean the Application can start safe again!
You could pass a command line argument like "restart" and run a Sleep() before you try to acquire the Mutex or try to acquire the mutex in a loop that sleeps a while.
Also you could set up communication between both processes, but that might be overkill.
hi take a look a the following article by Zarko Gajic - there you will get some ideas, sample code and even a whole component to use.
hth,
reinhard
Your ReleaseMutex is probably failing since you're passing 'False' for 'bInitialOwner' while calling CreateMutex. Either have the initial ownership of the mutex, or call CloseHandle instead of 'ReleaseMutex' passing your mutex handle.
checkout this way:
Simply runs a new application and kills the currernt one;
http://www.delphitricks.com/source-code/windows/restart_the_own_program.html
(beating the sleep idea)
if you want to make sure the original process is really terminated/closed before you create the mutex, then one idea is to pass the PID to the new process (command line is the easiest, any other IPC method works as well), then use OpenProcess(SYNCHRONIZE, false, pid) and WaitForSingleObject (I'd use a loop with a timeout (100 ms is a good value) and act accordingly if the original process takes too long to close)
What I ended up doing, beside the above, was to also create a RestartSelf procedure in the same unit with the mutex, and do the logic there, in order to keep the single instance and restart logic in the same place (the parameter being hardcoded, you don't want hardcoded stuff to be scattered around your application(s).
As far as I've been able to find out, Windows doesn't offer an API function to tell what application has registered a global hotkey (via RegisterHotkey). I can only find out that a hotkey is registered if RegisterHotkey returns false, but not who "owns" the hotkey.
In the absence of a direct API, could there be a roundabout way? Windows maintains the handle associated with each registred hotkey - it's a little maddening that there should be no way of getting at this information.
Example of something that likely wouldn't work: send (simulate) a registered hotkey, then intercept the hotkey message Windows will send to the process that registered it. First, I don't think intercepting the message would reveal the destination window handle. Second, even if it were possible, it would be a bad thing to do, since sending hotkeys would trigger all sorts of potentially unwanted activity from various programs.
It's nothing critical, but I've seen frequent requests for such functionality, and have myself been a victim of applications that register hotkeys without even disclosing it anywhere in the UI or docs.
(Working in Delphi, and no more than an apprentice at WinAPI, please be kind.)
One possible way is to use the Visual Studio tool Spy++.
Give this a try:
Run the tool (for me, it's at C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\Tools\spyxx_amd64.exe or you can download it). Note: there is spyxx.exe (32-bit version) and spyxx_amd64.exe (64-bit version) - if you don't see anything in 64-bit use the 32-bit version (ie.catches messages only in same architecture)
In the menu bar, select Spy -> Log messages... (or hit Ctrl + M)
Check All Windows in System in the Additional Windows frame
Switch to the Messages tab
Click the Clear All button
Select WM_HOTKEY in the listbox, or check Keyboard in Message Groups (if you're OK with more potential noise)
Click the OK button
Press the hotkey in question (Win + R, for example)
Select the WM_HOTKEY line in the Messages (All Windows) window, right click, and select Properties... in the context menu
In the Message Properties dialog, click the Window Handle link (this will be the handle for the window that received the message)
Click the Synchronize button on the Window Properties dialog. This will show the window in the main Spy++ window treeview (if it's windows itself or some popup application it shows nothing).
On the Window Properties dialog, select the Process tab
Click the Process ID link. This will show you the process (In my Win + R case: EXPLORER)
Your question piqued my interest, so I've done a bit of digging and while, unfortunately I don't have a proper answer for you, I thought I'd share what I have.
I found this example of creating keyboard hook (in Delphi) written in 1998, but is compilable in Delphi 2007 with a couple of tweaks.
It's a DLL with a call to SetWindowsHookEx that passes through a callback function, which can then intercept key strokes: In this case, it's tinkering with them for fun, changing left cursor to right, etc. A simple app then calls the DLL and reports back its results based on a TTimer event. If you're interested I can post the Delphi 2007 based code.
It's well documented and commented and you potentially could use it as a basis of working out where a key press is going. If you could get the handle of the application that sent the key strokes, you could track it back that way. With that handle you'd be able to get the information you need quite easily.
Other apps have tried determining hotkeys by going through their Shortcuts since they can contain a Shortcut key, which is just another term for hotkey. However most applications don't tend to set this property so it might not return much. If you are interested in that route, Delphi has access to IShellLink COM interface which you could use to load a shortcut up from and get its hotkey:
uses ShlObj, ComObj, ShellAPI, ActiveX, CommCtrl;
procedure GetShellLinkHotKey;
var
LinkFile : WideString;
SL: IShellLink;
PF: IPersistFile;
HotKey : Word;
HotKeyMod: Byte;
HotKeyText : string;
begin
LinkFile := 'C:\Temp\Temp.lnk';
OleCheck(CoCreateInstance(CLSID_ShellLink, nil, CLSCTX_INPROC_SERVER, IShellLink, SL));
// The IShellLink implementer must also support the IPersistFile
// interface. Get an interface pointer to it.
PF := SL as IPersistFile;
// Load file into IPersistFile object
OleCheck(PF.Load(PWideChar(LinkFile), STGM_READ));
// Resolve the link by calling the Resolve interface function.
OleCheck(SL.Resolve(0, SLR_ANY_MATCH or SLR_NO_UI));
// Get hotkey info
OleCheck(SL.GetHotKey(HotKey));
// Extract the HotKey and Modifier properties.
HotKeyText := '';
HotKeyMod := Hi(HotKey);
if (HotKeyMod and HOTKEYF_ALT) = HOTKEYF_ALT then
HotKeyText := 'ALT+';
if (HotKeyMod and HOTKEYF_CONTROL) = HOTKEYF_CONTROL then
HotKeyText := HotKeyText + 'CTRL+';
if (HotKeyMod and HOTKEYF_SHIFT) = HOTKEYF_SHIFT then
HotKeyText := HotKeyText + 'SHIFT+';
if (HotKeyMod and HOTKEYF_EXT) = HOTKEYF_EXT then
HotKeyText := HotKeyText + 'Extended+';
HotKeyText := HotKeyText + Char(Lo(HotKey));
if (HotKeyText = '') or (HotKeyText = #0) then
HotKeyText := 'None';
ShowMessage('Shortcut Key - ' + HotKeyText);
end;
If you've got access to Safari Books Online, there is a good section about working with shortcuts / shell links in the Borland Delphi 6 Developer's Guide by Steve Teixeira and Xavier Pacheco. My example above is a butchered version from there and this site.
Hope that helps!
After some research, it appears that you'd need to get access to the internal structure that MS uses to store the hotkeys. ReactOS has a clean room implementation that implements the GetHotKey call by iterating an internal list and extracting the hotkey that matches the parameters to the call.
Depending on how close ReactOS' implementation is to the MS implementation, you may be able to poke around in memory to find the structure, but that's over my head...
BOOL FASTCALL
GetHotKey (UINT fsModifiers,
UINT vk,
struct _ETHREAD **Thread,
HWND *hWnd,
int *id)
{
PHOT_KEY_ITEM HotKeyItem;
LIST_FOR_EACH(HotKeyItem, &gHotkeyList, HOT_KEY_ITEM, ListEntry)
{
if (HotKeyItem->fsModifiers == fsModifiers &&
HotKeyItem->vk == vk)
{
if (Thread != NULL)
*Thread = HotKeyItem->Thread;
if (hWnd != NULL)
*hWnd = HotKeyItem->hWnd;
if (id != NULL)
*id = HotKeyItem->id;
return TRUE;
}
}
return FALSE;
}
I presume this thread on sysinternals was asked by someone related to this question, but I thought I'd link to it anyway to keep the two together. The thread looks very intriguing, but I suspect that some deep dive spelunking would need to happen to figure this out without access to the MS internals.
Off the top of my head, you might try enumerating all windows with EnumWindows, then in the callback, send WM_GETHOTKEY to each window.
Edit: Apparrently I was wrong about that. MSDN has more information:
WM_HOTKEY is unrelated to the WM_GETHOTKEY and WM_SETHOTKEY hot keys. The WM_HOTKEY message is sent for generic hot keys while the WM_SETHOTKEY and WM_GETHOTKEY messages relate to window activation hot keys.
Note: Here is a program purporting to have the functionality you are looking for. You could try decompiling it.
Another thread mentions a global NT level keyboard hook:
Re-assign/override hotkey (Win + L) to lock windows
maybe you can get the handle of the process that called the hook that way, which you can then resolve to the process name
(disclaimer: I had it in my bookmarks, haven't really tried/tested)
I know you can intercept the stream of messages in any window within your own process - what we used to call subclassing in VB6. (Though I do not remember the function, perhaps SetWindowLong?) I am unsure if you can do this for windows outside your own process. But for the sake of this post lets assume you find a way to do that. Then you can simply intercept the messages for all top level windows, monitor for the WM_HOTKEY message. You wouldn't be able to know all the keys right off the bat, but as they were pressed you could easily figure out what application was using them. If you persisted your results to disk and reloaded each time your monitor application was run you could increase the performance of your application over time.
This doesn't exactly answer the part of the question that is about the Windows API, but it answers the part of the question that is about a list of global hotkeys and the applications that "own" them.
The free Hotkey Explorer at http://hkcmdr.anymania.com/ shows a list of all global hotkeys and the applications that own them. This just has helped me figure out why an application-specific shortcut key stopped working and how to fix it (by reconfiguring the registered global hotkey in the app that had it registered), within a few seconds.