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INPUT/OUTPUT FUNCTIONS
25.3 -- Device Independent 1/0 Functions
IOCSUF
must
contain
a
valid
MDOS-~ormatted
suffix
unless
the
non-file
format
mode
has
been
speciried in the IOCDTT or unless the
first
byte
or
IOCNAM
contained
a
binary zero
(see above).
IOCFDF
must
only
be
initialized
to
specify the file format (FMT bits) if
the output mode (M
=
lOoT IOCDTT) or
the update
mode
to
a
non-existing
file (M = 11
of
IOCDTT) is indicated.
In addition,
if the
device
type·
is
OK,
the other
bits of
IOCFDF must be
specified for these two
open
modes.
A special
case exists
ir the non-Tile
fo~mat
mode
is
indicated
in
the
IOCDTT.
In
th
i
s
i
nstanc e,
th e FMT
bits
of
IOCFDF
must
be
set
to
the
ASCII
~ecord
format (FMT
=
5).
It
is
not
~ecommended
that diskette
files be created with the
protection
at
tl" i
but e
s s e
t I S
in c e
the
y .
1&1
i 11
prevent a
rile
from
being
deleted
upon
closing
if
no information
was
wr itt en
in t o t h e ·
f i 1
e.
Th
e
protection
attl"ibutes
should be set
via the .
CHANG
system function or via
the
NAME
command.
IOCSBP
must be initialized if the device
type is OK and either the output mode
(M
=
10 of IOCDTT) or the update mode
to
a
non-~xisting
file
(M=11
of
IOCDTT)
is
specified.
A
value of
zero will
cause the default space
to
be
initially
allocated to the file.
A
non-zero
value
will
cause
that
number
of sectors to be used
fo~
the
initial allocation.
A
non-zero
value
in
IOCSBP
when
opening an existing file will have no
affect on the allocation
Or
the file.
Existing
files
only
change in size
when writing beyond
the
end-of-file
or
when
closing
them
with
the
truncate flag set.
IOCSBS must contain the starting
address
of
a
sector
buffer
only
if
the
devi~e
type is OK.
The sector buffer
must be an integral number of sectors
Page
25-36
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