how can I synchronize a gtk::label with the creation or suppression of a file in a directory?

Question

I have a program who lists all files in the working directory (I use glib for doing this), then I screen this list in a GtkWindow trough a Gtk::Label. I screen the window by using run(),

  Glib::RefPtr<Gtk::Application> app = Gtk::Application::create(argc, argv, "Zombie-Shadowchaser SixSixSix");
app->run(*pMainWindow);

I know how to change the label with set_label() I can synchronize the list of files in the directory with the list screened trough the click of a button. So if I delete or create a file, it will remove or add to the label the file. But how can I make my program to synchronize every second without clicking ?

You will need to use a filesystem notification API. I do not know if GLib provides one; maybe GVFS does if GLib doesn't? — andlabs, Jan 18 '15 at 17:57
@andlabs, thx for your comment, I shall do some search on internet. I never worked with "filesystem notification API" so far. A very quick search leads me to `inotify` — The Unholy Metal Machine, Jan 18 '15 at 18:03
GIO provides one which is cross-platform compatible. https://developer.gnome.org/gio/stable/GFileMonitor.html — nemequ, Jan 18 '15 at 19:56
@nemequ actualy your comment answer to my question, if you want the point post it as a question. Also I will put a complete example of use — The Unholy Metal Machine, Jan 18 '15 at 22:29

The Unholy Metal Machine · Accepted Answer · 2015-01-19T00:50:52.097

here a full example, is also good to study if you are looking to understand how to use g_signal_connect()

#include <gtkmm.h>

Gtk::Label *plabel; // because I"m lazzy...

/**
 ** everytime a file is created in the current directory, toCallbackFunction()
 ** will be called. The paramaters are the same of signal see signal here :
 ** http://www.freedesktop.org/software/gstreamer-sdk/data/docs/latest/gio/GFileMonitor.html#GFileMonitor-changed
 **/
void
toCallbackFunction(GFileMonitor      *monitor
                  ,GFile             *file
                  ,GFile             *other_file
                  ,GFileMonitorEvent event_type
                  ,gpointer          user_data
                  ) 
{
  plabel->set_label( g_file_get_path(file) );
}



int 
main(int  argc 
    ,char *argv[]
    )
{
  Glib::RefPtr<Gtk::Application> app = Gtk::Application::create(argc, argv, "org.gtkmm.examples.base");
  Gtk::Window window;
  Gtk::Label label;
  window.set_default_size(800, 200);

  label.set_label("test");

  window.add(label);
  label.show();
  plabel = &label;

  /* 
   * g_file_monitor() requires a file, not a path. So we use g_file_new_for_path()
   * to convert the directory (this is for demonstration)
   */   
  GFile *file = g_file_new_for_path("."); 
  GFileMonitor *monitor;
  /*
   * http://www.freedesktop.org/software/gstreamer-sdk/data/docs/latest/gio/GFile.html#g-file-monitor
   */
  monitor = g_file_monitor_directory(file, G_FILE_MONITOR_NONE, nullptr, nullptr);
  /* 
   * the next line, is how to connect the monitor to a callback function when
   * the signal changed has been triggered.
   */
  g_signal_connect(monitor, "changed", G_CALLBACK (toCallbackFunction), nullptr);


  return app->run(window);
}

compile on linux :

 g++ main.cc -o simple `pkg-config gtkmm-3.0 --cflags --libs` -std=c++11

for MS Windows users, I'm not racist, but I don't know how to compile on windows. Any comment would be apreciate, I made this piece of code by my own. Thx to report any error.

How to use it :

when you start the program, go with your console in the same directory and create a new file, for example,

 $ echo "stack" > overflow

you should get something like :

enter image description here

Thx to nemequ

I don't care about reputation points. I'm much happier that you wrote up the answer and included some example code. I've upvoted you, you should accept your own answer. — nemequ, Jan 19 '15 at 03:17

how can I synchronize a gtk::label with the creation or suppression of a file in a directory?

1 Answers1