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# Copyright(c) 1986 Association of Universities for Research in Astronomy Inc.
include <knet.h>
include <config.h>
include "mtio.h"
# ZOPNMT -- Open magtape device at the specifed file. We are called indirectly
# by MTOPEN (via fopnbf), which sets up a new mtio device decriptor pointed
# to by NEW_MTCHAN, and passes it via the mtio common.
procedure zopnmt (iodev, acmode, mtchan)
char iodev[ARB] #I PACKED i/o device name string
int acmode #I file access mode
int mtchan #O return value (mt descriptor index)
int mt
pointer sp, pk_devcap
include "mtio.com"
define err_ 91
begin
call smark (sp)
call salloc (pk_devcap, SZ_DEVCAP, TY_CHAR)
# Pick up index of mt descriptor slot set up by MTOPEN. Make sure
# that we were called by MTOPEN and not somebody else.
mt = new_mtchan
if (mt < 1 || mt > MT_MAXTAPES)
goto err_
# Open the device.
call strpak (Memc[MT_DEVCAP(mt)], Memc[pk_devcap], SZ_DEVCAP)
call zzopmt (iodev, MT_ACMODE(mt), Memc[pk_devcap], MT_DEVPOS(mt),
MT_FILE(mt), MT_OSCHAN(mt))
if (MT_OSCHAN(mt) == ERR)
goto err_
# If "new_mtchan" is nonzero when ZCLSMT is called, it implies that
# CLOSE was called during error recovery due to an interrupt of ZZOPMT
# and the position of the tape is undefined. Clear the flag since the
# open is now complete and we were not interrupted.
new_mtchan = NULL
MT_FILNO(mt) = MT_FILE(mt)
call mt_savepos (mt)
mtchan = mt
call sfree (sp)
return
err_
# Z-routines can only return ERR in the event of an error.
MT_OSCHAN(mt) = NULL
call sfree (sp)
mtchan = ERR
end
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