#  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_GetScrollInfo - parse arguments for scrolling commands

=for category C Programming

=head1 SYNOPSIS

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

int
B<Tk_GetScrollInfo(>I<interp, argc, argv, dblPtr, intPtr>B<)>

=head1 ARGUMENTS

=over 4

=item Tcl_Interp *interp (in)

Interpreter to use for error reporting.

=item int argc (in)

Number of strings in I<argv> array.

=item char *argv[] (in)

Argument strings.  These represent the entire method, of
which the first word is typically the widget name and the second
word is typically B<xview> or B<yview>.  This procedure parses
arguments starting with I<argv>[2].

=item double *dblPtr (out)

Filled in with fraction from B<moveto> option, if any.

=item int *intPtr (out)

Filled in with line or page count from B<scroll> option, if any.
The value may be negative.

=back

=head1 DESCRIPTION

B<Tk_GetScrollInfo> parses the arguments expected by widget
scrolling commands such as B<xview> and B<yview>.
It receives the entire list of words that make up a method
and parses the words starting with I<argv>[2].
The words starting with I<argv>[2] must have one of the following forms:

 moveto fraction
 scroll number units
 scroll number pages

Any of the B<moveto>, B<scroll>, B<units>, and B<pages>
keywords may be abbreviated.
If I<argv> has the B<moveto> form, B<TK_SCROLL_MOVETO>
is returned as result and I<*dblPtr> is filled in with the
I<fraction> argument to the command, which must be a proper real
value.
If I<argv> has the B<scroll> form, B<TK_SCROLL_UNITS>
or B<TK_SCROLL_PAGES> is returned and I<*intPtr> is filled
in with the I<number> value, which must be a proper integer.
If an error occurs in parsing the arguments, B<TK_SCROLL_ERROR>
is returned and an error message is left in I<interp-E<gt>result>.

=head1 KEYWORDS

parse, scrollbar, scrolling command, xview, yview