integer*4 input_unit,max_include_nest,list_unit,output_unit,max_output
	parameter (input_unit=10)	!default input unit number-allow room
					!above it for growth for includes
	parameter (max_include_nest=20)
	parameter (list_unit=1)		!default list file unit number
	parameter (output_unit=50)	!default output file unit number
	parameter (max_output=9)	!highest output channel

	logical*1 l_output,l_list,l_list_open,l_debug
	logical*1 l_eof,l_sub,l_show
	common/io_flags/l_output,l_list,l_eof,l_sub,l_show,l_list_open,l_debug
	save /io_flags/

c	list file data
	integer*4 page_size
	integer*4 lines_left
	integer*4 page_number
	integer*4 line_count
	common/list_control/page_size,lines_left,page_number,line_count
	save /list_control/

c	input/output data
	integer*4 current_unit,output_channel
	common/input_control/current_unit,output_channel
	save /input_control/

	character*4 extention
	common/ext_common/extention
	save /ext_common/

	structure/input_stream_structure/
		logical	file_io
		integer*4	first_string
		integer*4	current_string
		integer*4	line_count
	endstructure
	record/input_stream_structure/input_stream(0:max_include_nest)
	structure/output_stream_structure/
		logical open
		integer*4 line_count
	endstructure
	record/output_stream_structure/output_stream(0:max_output)
	common/input_stream_common/input_stream,output_stream
	save /input_stream_common/