screen_column(_c)

	screen_column.i4.v = screen_column(window_id.i2.r, column.i4.r)

	screen_column.i4.v = screen_column_c(window_id.i2.v, column.i4.v)

	This routine converts a window column value into a screen column
	value.  If the window does not exist, a value of CBS_NO_WINDOW
	will be returned.

	window_id	window ID (use WMNGR_BACKGROUND for background window)
	column		column to be converted

	This function returns status values as follows:

	CBS_NO_WINDOW		requested window does not exist
	otherwise		equivalent screen column

	This function requires the following include files:

	cbslib_h, acnet_errors_h

	Related functions:

	screen_row(_c), window_row(_c), window_column(_c), intro_tv_windows

	C/C++ usage:

	short	window_id;
	int	screen_column;
	int	column = 1;

	screen_column = screen_column_c(window_id,column);