1	SUB SMG_CHANGE_DEF_ATTR(LONG Rendition,LONG Vir_disp_num)

	!---------------------------------------------------------------&
	!								&
	!		      SMG_CHANGE_DEF_ATTR			&
	!								&
	!		Creation Date:  3-July-1985			&
	!		Author:		Ken Messer			&
	! 		Purpose:        Change a virtual display's	&
	!				video Rendition			&
	!								&
	!		Modification history				&
	!								&
	!	Date	Description of change(s)			&
	!								&
	!---------------------------------------------------------------&
	!								&
	! Copyright (c) 1985 -	Ken Messer, Allied Electronics, Inc.,	&
	!			401 E. 8th St., Ft. Worth, TX  76102	&
	!								&
	! This software may be copied and distributed freely to anyone	&
	! for non-commerical use provided that this copyright notice is &
	! included.							&
	!---------------------------------------------------------------&

	OPTION TYPE = INTEGER, SIZE = INTEGER LONG

	%include "SMG$LIBRARY:SMG.DFN"

	DECLARE LONG 				Return_status,		&
						New_video_attr,		&
						Number_rows,		&
						Number_columns

	EXTERNAL LONG FUNCTION			SMG$Get_Display_Attr,	&
						SMG$Change_virtual_display

	EXTERNAL LONG CONSTANT	  		SS$_Normal,		&
						SMG$M_Blink,		&
						SMG$M_Bold,		&
						SMG$M_Reverse,		&
						SMG$M_Underline

	EXTERNAL STRING FUNCTION	Get_Error_Message(LONG)

	!---------------------------------------------------------------&
	!								&
	!		M a i n   P r o g r a m   L o g i c		&
	!								&
	!---------------------------------------------------------------&

	! Test the rendition mask and set the specified video attributes

	New_video_attr = 0
	New_video_attr = New_video_attr OR SMG$M_Blink		IF Rendition AND 1
	New_video_attr = New_video_attr OR SMG$M_Bold		IF Rendition AND 2
	New_video_attr = New_video_attr OR SMG$M_Reverse	IF Rendition AND 4
	New_video_attr = New_video_attr OR SMG$M_Underline	IF Rendition AND 8

	! get the number of rows and columns in the display - we'll use
	! the current values since we're not changing them

	Return_status = SMG$Get_Display_Attr(Display_id(Vir_disp_num),	&
		Number_rows, Number_columns,,,)

	IF Return_status AND SS$_Normal = 0   THEN
		PRINT Get_Error_Message(Return_status)
		STOP
	END IF

	! Call the SMG RTL routine to change the rendition

	Return_status = SMG$Change_virtual_display(Display_id(Vir_disp_num), &
		Number_rows,Number_columns,,New_video_attr,)

	! Check for error

	IF Return_status AND SS$_Normal = 0   THEN
		PRINT Get_Error_Message(Return_status)
		STOP
	END IF

	SUBEXIT

	END SUB