Tk_GetSelection - retrieve the contents of a selection

       Tcl_Interp *interp (in)                Interpreter to use for reporting errors.

       Tk_Window tkwin (in)                   Window  on  whose  behalf  to  retrieve  the selection (determines
                                              display from which to retrieve).

       Atom selection (in)                    The name of the selection to be retrieved.

       Atom target (in)                       Form in which to retrieve selection.

       Tk_GetSelProc *proc (in)               Procedure to invoke to process pieces of the selection as they are
                                              retrieved.

       void *clientData (in)                  Arbitrary one-word value to pass to proc.
________________________________________________________________________________________________________________

Tk_GetSelection retrieves the selection specified by the  atom  selection  in  the  format  specified  by
       target.   The  selection may actually be retrieved in several pieces; as each piece is retrieved, proc is
       called to process the piece.  Proc should have arguments and result that match the type Tk_GetSelProc:

              typedef int Tk_GetSelProc(
                      void *clientData,
                      Tcl_Interp *interp,
                      char *portion);

       The clientData and  interp  parameters  to  proc  will  be  copies  of  the  corresponding  arguments  to
       Tk_GetSelection.   Portion  will  be  a pointer to a string containing part or all of the selection.  For
       large selections, proc will be called several times with successive portions of  the  selection.   The  X
       Inter-Client  Communication  Conventions  Manual  allows a selection to be returned in formats other than
       strings, e.g. as an array of atoms or integers.  If this happens, Tk converts the selection back  into  a
       string  before calling proc.  If a selection is returned as an array of atoms, Tk converts it to a string
       containing the atom names separated by white space.  For any other format besides string, Tk  converts  a
       selection to a string containing hexadecimal values separated by white space.

       Tk_GetSelection  returns  to its caller when the selection has been completely retrieved and processed by
       proc, or when a  fatal  error  has  occurred  (e.g.  the  selection  owner  did  not  respond  promptly).
       Tk_GetSelection  normally  returns  TCL_OK;  if an error occurs, it returns TCL_ERROR and leaves an error
       message in interpreter interp's result.  Proc should also return either TCL_OK  or  TCL_ERROR.   If  proc
       encounters  an  error  in dealing with the selection, it should leave an error message in the interpreter
       result and return TCL_ERROR;  this will abort the selection retrieval.

       format, get, selection retrieval

Tk                                                     4.0                                  Tk_GetSelection(3tk)

       Tk_GetSelection - retrieve the contents of a selection

#include<tk.h>

       int
       Tk_GetSelection(interp,tkwin,selection,target,proc,clientData)