TIP #264: ADD FUNCTION TO RETRIEVE THE INTERPRETER OF A WINDOW 
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 Version:      $Revision: 1.8 $
 Author:       George Petasis <petasis_at_iit.demokritos.gr>
 State:        Final
 Type:         Project
 Tcl-Version:  8.5
 Vote:         Done
 Created:      Saturday, 01 April 2006
 URL:          https://tip.tcl-lang.org264.html
 Post-History: 

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 ABSTRACT 
==========

 This TIP proposes the addition of a new function in the Tk public API, 
 for retrieving a pointer to the Tcl interpreter that was used for 
 creating a window. 

 RATIONALE 
===========

 During the development of a Tk extension that adds a ClientMessage 
 handler under unix (tkdnd), I needed to get the pointer of the Tcl 
 interpreter that is associated with a window. When the ClientMessage 
 handler is called, only a Tk_Window pointer is passed, for the window 
 the ClientMessage is for. But if you want to execute Tcl code, you 
 don't have a Tcl interpreter... 

 Of course, you can try use any (cached) interpreter, but this can lead 
 to various problems, if it is not the interpreter that was used for 
 creating the window. Since Tk already has this information, adding a 
 function to return the associated interpreter for a Tk_Window pointer 
 will be relatively easy. 

 PROPOSED CHANGE 
=================

 A new public function (with signature /Tcl_Interp */ 
 *Tk_Interp*/(Tk_Window tkwin)/) is proposed to be added to the public C 
 API of Tk. This function can be implemented as follows: 

    Tcl_Interp *
    Tk_Interp(Tk_Window tkwin) {
        if (tkwin != NULL && ((TkWindow *) tkwin)->mainPtr != NULL) {
            return ((TkWindow *) tkwin)->mainPtr->interp;
        }
        return NULL;
    }

 COPYRIGHT 
===========

 This document has been placed in the public domain. 

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