window_column(_c)

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

	window_column.i4.v = window_column_c(window_id.i2.v, column.i4.v)

	This routine converts a TV column value into the column value relative
	to the window specified by "window_id".  If the column value lies
	outside of the window, a value of CBS_NOT_IN_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
	CBS_NOT_IN_WINDOW	requested column is not in the window
	otherwise		equivalent window column

	This function requires the following include files:

	cbslib_h, acnet_errors_h

	Related functions:

	window_row(_c), screen_row(_c), screen_column(_c), intro_tv_windows

	C/C++ usage:

	short	window_id;
	int	window_column;
	int	column = 10;

	window_column = window_column_c(window_id,column);