#  Copyright (c) 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_ClipboardClear, Tk_ClipboardAppend - Manage the clipboard

=for category C Programming

=head1 SYNOPSIS

B<#include E<lt>tk.hE<gt>>

int
B<Tk_ClipboardClear>(I<interp, tkwin>)

int
B<Tk_ClipboardAppend>(I<interp, tkwin, target, format, buffer>)

=head1 ARGUMENTS

=over 4

=item Tcl_Interp *interp (in)

Interpreter to use for reporting errors.

=item Tk_Window tkwin (in)

Window that determines which display's clipboard to manipulate.

=item Atom target (in)

Conversion type for this clipboard item;  has same meaning as
I<target> argument to B<Tk_CreateSelHandler>.

=item Atom format (in)

Representation to use when data is retrieved;  has same meaning as
I<format> argument to B<Tk_CreateSelHandler>.

=item char *buffer (in)

Null terminated string containing the data to be appended to the clipboard.

=back

=head1 DESCRIPTION

These two procedures manage the clipboard for Tk.
The clipboard is typically managed by calling B<Tk_ClipboardClear>
once, then calling B<Tk_ClipboardAppend> to add data for any
number of targets.

B<Tk_ClipboardClear> claims the CLIPBOARD selection and frees any
data items previously stored on the clipboard in this application.
It normally returns TCL_OK, but if an error occurs it returns
TCL_ERROR and leaves an error message in I<interp-E<gt>result>.
B<Tk_ClipboardClear> must be called before a sequence of
B<Tk_ClipboardAppend> calls can be issued.

B<Tk_ClipboardAppend> appends a buffer of data to the clipboard.
The first buffer for a given I<target> determines the I<format>
for that I<target>.
Any successive appends for that I<target> must have
the same format or an error will be returned.
B<Tk_ClipboardAppend> returns TCL_OK if the buffer is
successfully copied onto the clipboard.  If the clipboard is not
currently owned by the application, either
because B<Tk_ClipboardClear> has not been called or because
ownership of the clipboard has changed since the last call to
B<Tk_ClipboardClear>,
B<Tk_ClipboardAppend> returns TCL_ERROR and leaves an error message in
I<interp-E<gt>result>.

In order to guarantee atomicity, no event handling should occur
between B<Tk_ClipboardClear> and the following
B<Tk_ClipboardAppend> calls (otherwise someone could retrieve
a partially completed clipboard or claim ownership away from
this application).

B<Tk_ClipboardClear> may invoke callbacks, including arbitrary
Callbacks, as a result of losing the CLIPBOARD selection, so
any calling function should take care to be reentrant at the point
B<Tk_ClipboardClear> is invoked.

=head1 KEYWORDS

append, clipboard, clear, format, type
