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INPUT/OUTPUT FUNCTIONS
25.3 -- Device Independent I/O Functions
that the IOCB has been
~eserved.
The IOCLUN Tield
must
not
be
changed
by the calling program aTter the .RESRV function
has been called.
25.3.1.8 IOCNAM -- File name
These eight bytes of the IOCB serve a dual purpose.
If
the
non-file
rormat
mode
is being used (F
=
1 of IOCDTT),
IOCNAM is not used at a 1
h
however,
in th e f
i
1 e format
mod e,
IOCNAM must contain the name of the file to be accessed.
The
file name must be in the valid MDOS file
name
format.
Any
unused parts of the name must be spaces ($20),
The file name
should be placed into IOCNAMbefore
the
.OPEN
function
is
invoked.
Arter a file has been opened!
the eight bytes will
be replaced with the four
two-byte
fields
IOCMLS,
IOCSDW,
IOCSLSI and IOCLSN (only if the device is diskette).
When
dealing
with
non-diskette
devices
in
the file
fo~mat
mode,
the IOCNAM entry can be configured so
that
the
f
i
~st
by te
is
a
binary
z era.
In
th is
ease,
the . OPEN
function will search
~O~
the first FDR
on
the
non-diskette
device,
and
place
the
'ound
file
name (and suffix) into
IOCNAM (and IOCSUF >.
25. 3.
1.
9
IOCSUF --
Suff
i
x
This two-byte field of the IOCB serves
a
dual
purpose.
If
the non-file Tormat mode is being used (F
=
1 of IOCDTT)
I
I DC SUF i s not u's e d
a
tal I ; h
0 bI
eve T' l i n the f
i
1 e
r
0
~
ma
t
mod e ,
IOCSUF
must
contain
the suffix
Or
the file to
b~
accessed.
The suffix must be in the
valid
MDOS
suffix
format.
Any
unused
parts of the suffix must be spaces ($20).
The suffix
should be placed into IOCSUF befoT'e
the
. OPEN
function
is
invoked
(at
the same time that the file name is placed into
IOCNAM>'
After a
file
has
been
opened,
IOCSUF
will
be
replaced
with
the two-byte field IOCEDF (only if the device
is diskette>.
If the device being
accessed
is
the
system
console,
the
Ti~st
character
of
the
IOCSUF field may be
c han g ed' b y
the
use,..
to
a
dis pIa
y
a b 1 eASe I I
c h a r act e T'
($20-$5F>'
Then}
wheneveT' an input request is made on that
device,
the characteT' will be displayed as an input prompt.
When dealing
with
non-diskette
devices
in
the
rile
format
mode,
the IOCNAM entry can be configured so that the
T
irs t b Y t e i s
a
bin a
r y
z e,..
0 .
I n t h i s
cas e,
the
. OP EN
function
will
sea~ch
fo~
the
fi~st
FDR on the non-diskette
device, and place the
found
rile
name
(and
sUrrix)
into
IOCNAM (and IOCSUF).
Page
25-24
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