Visualizza wikitesto di Individuare l'ID ed il nome di una finestra nonché il PID del programma mediante le funzioni del API di X11

La libreria '''X11''' ci consente anche di individuare il numero identificativo (''Id'') ed il nome di una qualsiasi finestra, nonché il PID del programma al quale quella finestra appartiene.

Sarà necessario richiamare la libreria del sistema X11: "''libX11.so.6.4.0'' ".


Mostriamo di seguito un possibile breve codice al riguardo:
 Private Const MAX_PROPERTY_VALUE_LEN As Integer = 4096
 
 Library "libX11:6.4.0"
 
 Private Const XA_CARDINAL As Integer = 6
 Private Const XA_WINDOW As Integer = 33
 
 <FONT Color=gray>' ''Display *XOpenDisplay(char *display_name)''
 ' ''Opens a connection to the X server that controls a display.''</font>
 Private Extern XOpenDisplay(display_name As Pointer) As Pointer
 
 <FONT Color=gray>' ''Window XDefaultRootWindow(Display *display)''
 ' ''Return the root window for the default screen.''</font>
 Private Extern XDefaultRootWindow(displayP As Pointer) As Integer
 
 <FONT Color=gray>' ''Atom XInternAtom(Display *display, char *atom_name, Bool only_if_exists)''
 ' ''Returns the atom identifier associated with the specified atom_name string.''</font>
 Private Extern XInternAtom(displayP As Pointer, atom_name As String, only_if_exists As Boolean) As Integer
 
 <FONT Color=gray>' ''int XGetWindowProperty(Display *display, Window w, Atom property, long long_offset, long long_length, Bool delete, Atom req_type, Atom *actual_type_return, int *actual_format_return, unsigned long *nitems_return, unsigned long *bytes_after_return, unsigned char **prop_return)''
 ' ''Returns the actual type of the property; the actual format of the property.''</font>
 Private Extern XGetWindowProperty(display As Pointer, w As Long, property_ As Integer, long_offset As Long, long_length As Long, delete As Boolean, req_type As Integer, actual_type_return As Pointer, actual_format_return As Pointer, nitems_return As Pointer, bytes_after_return As Pointer, prop_return As Pointer) As Integer
 
 <FONT Color=gray>' ''Status XGetWMName(Display *display, Window w, XTextProperty *text_prop_return)''
 ' Calls XGetTextProperty() to obtain the WM_NAME property.''</font>
 Private Extern XGetWMName(display As Pointer, w As Long, text_prop_return As Pointer) As Integer
 
 <FONT Color=gray>' ''XCloseDisplay (Display *display)''
 ' ''Closes a display or disconnect from the X server.''</font>
 Private Extern XCloseDisplay(displayP As Pointer)
  
 
 '''Public''' Sub Main()
 
  Dim disp, datID, p, datPID As Pointer
  Dim x_num_Atom, tipo, formato As Integer
  Dim err, n_fin, bytes_succ, i, pid As Integer
  Dim rootW As Long
  Dim stId, stPid As Stream
  Dim b As Byte
  Dim id As String
 
  disp = XOpenDisplay(0)
  If disp == 0 Then Error.Raise("Impossibile aprire lo schermo !")
    
  rootW = XDefaultRootWindow(disp)
    
  x_num_Atom = XInternAtom(disp, "_NET_CLIENT_LIST", False)
    
  err = XGetWindowProperty(disp, rootW, x_num_Atom, 0, MAX_PROPERTY_VALUE_LEN / 4, False, XA_WINDOW, VarPtr(tipo), VarPtr(formato), VarPtr(n_fin), VarPtr(bytes_succ), VarPtr(datID))
  If err <> 0 Then Error.Raise("Impossibile ottenere dati dalla funzione 'XGetWindowProperty' !")
    
  If XA_WINDOW <> tipo Then Error.Raise("Tipo invalido di proprietà '_NET_CLIENT_LIST' !")
    
  Print "Id", Null, "PID", "Nome finestra\n"
    
  p = Alloc(SizeOf(gb.Byte), 32)
    
  stId = Memory datID For Read
 
  For b = 1 To n_fin * 2
    Read #stId, i
    If i > 0 Then
      XGetWMName(disp, i, p)
      id = Hex(i)
      x_num_Atom = XInternAtom(disp, "_NET_WM_PID", False)
      err = XGetWindowProperty(disp, i, x_num_Atom, 0, MAX_PROPERTY_VALUE_LEN / 4, False, XA_CARDINAL, VarPtr(tipo), VarPtr(formato), VarPtr(n_fin), VarPtr(bytes_succ), VarPtr(datPID))
      If err <> 0 Then Error.Raise("Impossibile ottenere dati dalla funzione 'XGetWindowProperty' !")
      If datPID > 0 Then
        stPid = Memory datPID For Read
        Read #stPid, pid
      Endif
      Print id, Null, pid, String@(Pointer@(p))
    Endif
  Next
      
 <FONT Color=gray>' ''Va in chiusura:''</font>
  stPid.Close
  stId.Close
  Free(p)
  XCloseDisplay(disp)
 
 '''End'''