According to this question : Boost::process hide console on windows
How can I achieve the same but on Linux platform using boost::process ? (prevent console window creation on the newly spawn child process)
My use case is as followed:
I'm trying to call a cross-platform GUI app built from .NET 5.0 AvaloniaUI (C#). And I'm calling that from another GUI app built from gtkmm (c++). It does create black console along with GUI window.
This symptom doesn't occur when I tried calling the same mentioned Avalonia app with another cross-platform Avalonia app. It doesn't create any console, only the GUI window as intended. (Using System.Diagnostics.Process from .NET C#).
So maybe there is some detail behind that make these api behave differently? (boost::process / System.Diagnostics.Process)
Basically I'm looking for the api to do the same thing with System.Diagnostics.Process (C#) on c++
On linux a new console isn't created anyways. So, the only thing you might want to do is prevent the child process from sharing the parent's, like so:
#include <boost/process.hpp>
namespace bp = boost::process;
int main() {
bp::child child(bp::search_path("xclock"), //
bp::std_in.null(), //
bp::std_out.null(), //
bp::std_err.null());
child.wait();
}
If, on the other hand, you would like to create a terminal, you have to tell the OS which one you want and how to start that:
bp::child child(bp::search_path("gnome-terminal"), //
std::vector<std::string>{"-x", "/usr/bin/htop"}, //
bp::std_in.null(), //
bp::std_out.null(), //
bp::std_err.null());
Or, e.g.
bp::child child(bp::search_path("gnome-terminal"), //
std::vector<std::string>{"-x", "/usr/bin/htop"}, //
bp::std_in.null(), //
bp::std_out.null(), //
bp::std_err.null());
Note that the gnome-terminal launcher forks (so it "returns" immediately, leaving the terminal running with the htop inside), but xterm does not. So, on UNIX, like ever, you have lots of choices.
Linux does not create new console, like the others suggested. (unless explicitly define to)
After more investigation, I found that, it's only a misunderstanding.
If you use some GUI lib (like GTKmm, in this case), and try to spawn new process, which is a GUI window also, there might be an afterimage-like effect if you don't do it asynchonously
(If that second GUI window is initialized with black background, like the one created with AvaloniaUI, you may confuse it as another console :p)
Related
I am trying to learn windows programming. I would like to launch an executable program.exe (say) from c++ code. I am able to achieve this by using CreateProcess() method in windows. However, my problem is if the process is already created and running in the background then the windows for program.exe should come to foreground otherwise a new process should be created and brought to the foreground. Any help will be appreciated.
Look at Win32 API functions such as the following:
to discover if a given process is running, you can use:
CreateToolHelp32Snapshot(TH32CS_SNAPPROCESS) with Process32First() and Process32Next(). See Taking a Snapshot and Viewing Processes.
or
EnumProcesses with OpenProcess() and GetModuleBaseName()/GetProcessImageFileName()/QueryFullProcessImageName(). See Enumerating All Processes.
to find an existing window, you can use:
FindWindow() or FindWindowEx(), if you know the window's class name or title text ahead of time.
or
EnumWindows() with GetClassName() and/or GetWindowText(), if the window's class name or title text are dynamic but follow a pattern you can look for.
to restore a window if it is minimized, you can use IsIconic() with SetWindowPos(SW_RESTORE).
to bring a window into the foreground, you can use BringWindowToTop() and/or SetForegroundWindow().
Is that program.exe written by you? This functionality is better handled there: on start you check if there is already an instance running and if there is - activate it.
Otherwise - what do you do if there are multiple instances of program.exe already running?
I have Application A which is a third party Windows application (with GUI) that uses the Qt library.
I want to write Application B which will be responsible for starting Application A. I want Application B to also find buttons on Application B (QWidgets) and send them mouse inputs (click, double click etc).
I can run Application A through using the start function on a QProcess.
How do I do the following from my instance of the QProcess:
Get the top level window(s) for the process
Get a widget by name or (other identifiable attribute)
Get the widgets caption, colour and coordinates (and maybe some other data)
Send mouse move and click events to specific coordinates
Give a widget keyboard focus
Send keyboard key presses
Note - I know how to do this with the Windows API, but asking for a way via Qt. The specific Application A in question does not use the native windowing system, therefore window handles will not show up in Spy++ or Windows API functions.
Update 1 - Cannot seem to get any meaningful objects through the process's children
My attempt at getting child widgets for the process:
QProcess* process = new QProcess();
QString program = "\"C:\\Program Files (x86)\\foo\\bar.exe\"";
process->start(program);
auto widgets = process->findChildren<QWidget*>("", Qt::FindChildrenRecursively);
auto i = widgets.count();
// i = 0
If I find children of type <QObject*> I get 4 results. I used metaObject()->className() to see that I have two pairs of QWindowsPipeReader and QWinOverlappedIoNotifier objects.
Update 2 - Cannot create/inject window from another process
I noticed that when I run the QProcess I can use Windows API functions to get the top level window (top level only). I read in the Qt documentation that you can create a QWindow from the handle of a window in another process using QWindow::fromWinId.
Using this function will throw an 0xC0000005: Access violation reading location 0x00000000. error. I am not passing in a null handle. I am using reinterpret_cast to get the HWND to a WId type. It creates a QWindow only when I create a QApplication beforehand.
The new QWindow will have no children (using window->findChildren<QObject*>("", Qt::FindChildrenRecursively); I assume that the creation of the QWindow does not bring across associated child widgets.
Update 3 - I am currently reading into whether inter-process communication can be used
I have come across various threads, questions and code snippets regarding ICP in Qt. I don't see anything so far that specifically shows that ICP is possible when one of the processes is third party.
I have seen that the Squish Gui test tool lets you interrogate QWidget properties.
This will never work the way you intend it to.
If you really wish to take direct control over the other application, you must inject your code into that application. Let's assume that the application uses a dynamically linked Qt. Then:
Build a binary-compatible version of Qt, using the same compiler that was used to build the application you intend to tweak.
Replace the application's Qt with yours. Everything should still work fine, given that yours should be binary compatible. If not, the binary compatibility isn't there, and you must tweak things until they work.
Edit your Qt to add a hook to initialize your code at the end of QApplication constructor. This makes the Qt module that provides QApplication dependent on your code.
Put your code into a dll that the widgets (for Qt 5) or gui (for Qt 4) module is now dependent on.
Again replace the app's Qt with yours, with hooks that start your code.
Your code will of course need to be asynchronous, and will be monitoring the application's progress by inspecting the qApp->activeWindow(), qApp->allWidgets(), etc.
That's pretty much the only way to do it. You can of course inject your code in any other way you desire, but you will need to work with a binary-compatible version of Qt just to compile your code. Note that binary compatibility encompasses more than merely using the same compiler version and Qt version. Many of the configure switches must be the same, too.
In our project we have three independent applications, and we have to develop a QT control application that controls these three applications. The main window will be seperated to three sub windows - each one display another one application.
I thought to use QX11EmbedWidget and QX11EmbedContainer widgets, but two problems with that:
The QX11Embed* is based on X11 protocol and I dont know if it's supported on non-x11 systems like Windows OS.
Since QT 5 these classes are not existing, and the QT documentation doesn't mention why.
So that I dont know whether to use it or not - I'll be happy to get an answers.
In addition, I see that the QT 5.1 contains QWidget::createWindowContainer(); function that in some posts it looks like this should be the replacement to the X11Embed. Can anyone please explian me more how can I use this function to create a QT widget that will run another application (a Calculator for example) inside its?
I have searched a lot in Google, and didn't find answers to my Qs.
Can anyone please help me? Am I on the right way?
Thanks!
If all three independent applications are written with Qt, and you have their source, you should be able to unify them just through the parenting of GUI objects in Qt.
http://qt-project.org/doc/qt-4.8/objecttrees.html
http://qt-project.org/doc/qt-4.8/widgets-and-layouts.html
http://qt-project.org/doc/qt-4.8/mainwindows-mdi.html
If you don't have access to them in that way, what you are talking about is like 3rd party window management. It is kind of like writing a shell, like Windows Explorer, that manipulates the state and the size of other window applications.
Use a program like Spy++ or AutoIt Spy for Windows and the similar ones for other OS's, and learn the identifying markings of your windows you want to control, like the class, the window title, etc. Or you can launch the exe yourself in a QProcess::startDetached() sort of thing.
http://qt-project.org/doc/qt-5.1/qtcore/qprocess.html#startDetached
Then using the OS dependent calls control the windows. The Qt library doesn't have this stuff built in for third party windows, only for ones under the QApplication that you launched. There are a lot of examples of doing things like this by AutoHotKey, or AHK. It is a scripting language that is made for automating a lot of things in the windows environment, and there is port for Mac as well (though I haven't tried the mac port myself).
So in the end you are looking at finding your window probably with a call like this:
#include <windows.h>
HWND hwnd_1 = ::FindWindow("Window_Class", "Window Name");
LONG retVal = GetWindowLongA(hwnd_1, GWL_STYLE); // to query the state of the window
Then manipulate the position and state of the window like so:
::MoveWindow(hwnd_1, x, y, width, height, TRUE);
::ShowWindow(hwnd_1, SW_SHOWMAXIMIZED);
You can even draw widgets on top of the windows you are controlling if you set your window flags correctly for the windows you are manipulating.
transparent QLabel with a pixmap
Cannot get QSystemTrayIcon to work correctly with activation reason
Some gotchas that come up in Windows when doing all of this, is finding out the quirks of the Windows UI when they set the Display scaling different from what you expect, and if you want to play nice with the Task bar, and handling all the modal windows of your programs you are manipulating.
So overall, it is do-able. Qt will make a nice interface for performing these commands, but in the end you are looking at a lot of work and debugging to get it in a beautiful, reliable, window manager.
Hope that helps.
I never tried it myself, but from the docs in Qt 5.1 I would try QWindow::fromId(WId id), which gives you a QWindow, which should be embeddable with createWindowContainer:
QWindow * QWindow::fromWinId(WId id) [static] Creates a local
representation of a window created by another process or by using
native libraries below Qt.
Given the handle id to a native window, this method creates a QWindow
object which can be used to represent the window when invoking methods
like setParent() and setTransientParent(). This can be used, on
platforms which support it, to embed a window inside a container or to
make a window stick on top of a window created by another process.
But no guarantee. :-)
I'd like to create a tool that can either act as command line (display some console output based on input parameters), or display a window, based on input parameters.
I'm using MSV2012 with C++, and it seems you have to 'choose' between console and window app.
I know the net is filled with samples which use AllocConsole() and redirect std::out, but it doesn't make it feel like a command line application : calling the exe from the windows console will open a new window with the console output...
Is there a way to have it use the current console window instead of allocating a new one?
If not possible, I'll make 2 applications instead, but that's a pity..
Someone else may have a more authoritative answer, but I don't believe it's supported.
The usual workaround is to create a Windows app, but have a command-line wrapper that launches it from the CLI (and provides a channel for communicating with the original console).
It's not technically supported but I found a good solution by getting a snapshot for the current process, finding the parent process, attaching to it's console if it's a console app or creating one with AllocConsole, redirecting the output, getting the thread of the parent process if it's cmd.exe and suspending it, resuming it just before I exit my app
I'm trying to make a Windows app that checks some things in the background, and inform the user via a systray icon.
The app is made with Not managed C++ and there is no option to switch to .net or Java.
If the user wants to stop the app, he will use the tray icon.
The app can't be a Service because of the systray side and because it must run without installing anything on the user computer ( it's a single .exe )
Using the typical Win32 program structure ( RegisterClass, WndProc and so on ) i dont know how can i place some code to run apart the window message loop.
Maybe i have to use CreateProcess() or CreateThread()? Is It the correct way to handle the Multithreading environment?
If i have to use CreateProcess()/CreateThread(), how can i comunicate between the two threads?
Thanks ;)
As for the system tray icon, you'll need Shell_NotifyIcon.
See http://msdn.microsoft.com/en-us/library/bb762159.aspx
I doubt you want to create new processes to do this, you want to create a thread in your application. The API to do this is CreateThread. But if you are using C++, you should really be investigating the use of frameworks and class libraries to do this, not writing what will effectively be C code from scratch.
All threads belonging to an application share the global variables of the application, which can thus be used for communication. You will need to protect such multi-threaded access with something like a critical section.