/*  vs_clr.c

    *********** Copyright 1988-1993 by Vermont Creative Software ***********

vs_clr()
Clears the screen

Call

#include <vv_sys.h>

void vs_clr()

Returns

None

Description

vs_clr() clears the entire screen with spaces using the screen 
clear attribute.  The clear attribute is assigned an initial value of LSYS. 
This value can be changed within the program using vs_clratt().

UNIX and VMS Systems:

If a clear screen escape sequence has been defined, it will be used to
clear the screen; otherwise, the screen will be filled with blanks. 
The escape sequence approach is much faster and is the preferred
method.

If the escape sequence is used to clear the screen and the global
clear attribute is not NORMAL, the current video attribute for the
terminal is set to the global clear attribute.  The escape sequence
is then sent to the terminal to clear the screen.  If the screen
can only be cleared to NORMAL, spaces are used to clear the screen
instead.

*/

#include <vv_sys.h>

#ifdef OLD_STYLE
void FASTCALL vs_clr()
#else
void FASTCALL vs_clr(void)
#endif
{
    WINDOWPTR ttop_child;
    ULONG flags;
#ifndef NO_DEBUG_CODE
    static UCHAR fn[] = "vs_clr";
#endif

    INIT_MODULE(fn);

    sw_att(_vid_scr.clratt, FULL_WNP);	/* set to clear attribute   	      */

    ttop_child = FULL_WNP->top_child;
    FULL_WNP->top_child = (WINDOWPTR) NULLP;

    flags = FULL_WNP->flags;
    FULL_WNP->flags &= ~BUFFERED;	/* Enable fast screen clear	      */

    wn_clr(FULL_WNP);			/* clear entire window (screen)	      */

    FULL_WNP->flags = flags;		/* Restore flags and clear buffer     */
    v_chattrow(0, 0, FULL_WNP->fill_char, FULL_WNP->att, ENDWN, CHATT, FULL_WNP);
    cs_mv(0, 0, FULL_WNP);		/* reposition virtual cursor to origin*/
    FULL_WNP->top_child = ttop_child;

    EXIT_NOERRH(fn);
    return;
}