title	Module from library BASE_2 : CHNTST
	name	('CHNTST')
	maclib	baselib.lib

; Test if requested channel open

; Copyright (C)	Werner Cirsovius
;		Hohe Weide 44
;		D-20253 Hamburg
;		Tel.: +49-40-4223247

;		Version 1.0 February 1987

; ENTRY	Register C holds channel number 0 .. max

; EXIT	Carry set indicates error channel out of range
;	or not opened
;	On carry reset zero set indicates channel opened
;	for write operation otherwise for reading

	entry	@chtst

	extrn	@chacc

@chtst:
	push	hl
	call	@chacc		; Test channel in range
	jr	c,chnerr
	scf
	jr	nz,chnerr	; Should be open
	inc	hl
	ld	a,(hl)		; Get mode
	or	a		; Set no error
chnerr:
	pop	hl
	ret

	end