Tk_Grab(3)

Tk_Grab(3)            Tk Library Procedures            Tk_Grab(3)

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NAME

     Tk_Grab, Tk_Ungrab - manipulate grab state in an application

SYNOPSIS

     #include <tk.h>

     int
     Tk_Grab(interp, tkwin, grabGlobal)

     void
     Tk_Ungrab(tkwin)

ARGUMENTS

     Tcl_Interp *interp (in)                   Interpreter to use
                                               for  error report-
                                               ing

     Tk_Window tkwin (in)                      Window  on   whose
                                               behalf the pointer
                                               is to  be  grabbed
                                               or released

     int grabGlobal (in)                       Boolean indicating
                                               whether  the  grab
                                               is    global    or
                                               application local
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DESCRIPTION

     These functions are used to  set  or  release  a  global  or
     application  local grab.  When a grab is set on a particular
     window in a Tk application, mouse and  keyboard  events  can
     only  be received by that window and its descendants.  Mouse
     and keyboard events for windows outside the tree  rooted  at
     tkwin  will  be redirected to tkwin.  If the grab is global,
     then all mouse and keyboard events for windows  outside  the
     tree  rooted  at  tkwin  (even those intended for windows in
     other applications) will be redirected  to  tkwin.   If  the
     grab  is  application  local, only mouse and keyboard events
     intended for a windows within the same application (but out-
     side the tree rooted at tkwin) will be redirected.

     Tk_Grab sets a grab on a particular window.  Tkwin specifies
     the  window  on  whose  behalf the pointer is to be grabbed.
     GrabGlobal indicates whether the grab should  be  global  or
     application  local;  if  it  is  non-zero, it means the grab
     should be global.  Normally, Tk_Grab returns TCL_OK;  if  an

Tk                        Last change:                          1

Tk_Grab(3)            Tk Library Procedures            Tk_Grab(3)

     error  occurs  and  the  grab  cannot  be  set, TCL_ERROR is
     returned and an error message is left  if  interp's  result.
     Once this call completes successfully, no window outside the
     tree rooted at tkwin  will  receive  pointer-  or  keyboard-
     related  events until the next call to Tk_Ungrab.  If a pre-
     vious grab was in effect within the application, then it  is
     replaced with a new one.

     Tcl_Ungrab releases a grab on the  mouse  pointer  and  key-
     board,  if  there  is  one set on the window given by tkwin.
     Once a grab is released, pointer and  keyboard  events  will
     start being delivered to other windows again.

KEYWORDS

     grab, window

Tk                        Last change:                          2