# Copyright (c) 1990-1994 The Regents of the University of California.
# Copyright (c) 1994-1996 Sun Microsystems, Inc.
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
#
=head1 NAME
Tk_GetSelection - retrieve the contents of a selection
=for category C Programming
=head1 SYNOPSIS
B<#include E<lt>tk.hE<gt>>
int
B<Tk_GetSelection>(I<interp, tkwin, selection, target, proc, clientData>)
=head1 ARGUMENTS
=over 4
=item Tcl_Interp *interp (in)
Interpreter to use for reporting errors.
=item Tk_Window tkwin (in)
Window on whose behalf to retrieve the selection (determines
display from which to retrieve).
=item Atom selection (in)
The name of the selection to be retrieved.
=item Atom target (in)
Form in which to retrieve selection.
=item Tk_GetSelProc *proc (in)
Procedure to invoke to process pieces of the selection as they
are retrieved.
=item ClientData clientData (in)
Arbitrary one-word value to pass to I<proc>.
=back
=head1 DESCRIPTION
B<Tk_GetSelection> retrieves the selection specified by the atom
I<selection> in the format specified by I<target>. The
selection may actually be retrieved in several pieces; as each piece
is retrieved, I<proc> is called to process the piece. I<Proc>
should have arguments and result that match the type
B<Tk_GetSelProc>:
typedef int Tk_GetSelProc(
ClientData clientData,
Tcl_Interp *interp,
char *portion);
The I<clientData> and I<interp> parameters to I<proc>
will be copies of the corresponding arguments to
B<Tk_GetSelection>. I<Portion> will be a pointer to
a string containing part or all of the selection. For large
selections, I<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 I<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.
B<Tk_GetSelection> returns to its caller when the selection has
been completely retrieved and processed by I<proc>, or when a
fatal error has occurred (e.g. the selection owner didn't respond
promptly). B<Tk_GetSelection> normally returns TCL_OK; if
an error occurs, it returns TCL_ERROR and leaves an error message
in I<interp-E<gt>result>. I<Proc> should also return either
TCL_OK or TCL_ERROR. If I<proc> encounters an error in dealing with the
selection, it should leave an error message in I<interp-E<gt>result>
and return TCL_ERROR; this will abort the selection retrieval.
=head1 KEYWORDS
format, get, selection retrieval