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INPUT/OUTPUT FUNCTIONS
25.3 -- Device Independent IIO Functions
not
to
LP
or
eN),
File-type devices are those which use a
medium that can be re-read later.
I f
the
lOeB
has been opened in the update modes
(M
=
00
or 11 of
IOCDTT),
then . CLOSE will perfoTm the same functions
as in the input or the output
mode
depending on the last
IIO
t-ransfer
t'dpe.
The.
GETRC
and.
GETLS
functions will set
IO
of
IOCDTT
to indicate an input t-rans-re'1',
while the
.PUTRC
and
.PUTLS
functions will set
IO
of
IOCDTT
to indicate an output
transfeT".
In the latter case,
space is only
deallocated
if
the
truncate
flag
(T
of
IOCDTT)
is
set
to
one
(done
automatically when new space is allocated,
or done by user to
indicate
fil.
shortening or updating of end-aT-file pointer
in RIB),
ENTRY PARAMETERS:
EXIT CONDITIONS:
x
=
ihe aaaress
oT
an IOCE which has been
properly
reserved
and opened (i. e.
I
no errors occurred)
via
the
.RESRV
and . OPEN functionsl
respectively.
Normall~,
no
additional
parameteT"s
are rea.uiredi
however,
when
dealing
with
diskette
files
in
the update
mode
(M
=
00
or
11
o-r
lOCDTT),
the
truncate
flag
(T
o~
IOCDTT)
and
the
maximum
referenced
logical
sector
number
(IOCMLS) can be configured by
the
calling
program.
Since
the
update
modes
only
set the truncate
flag to one if a
new
file is
created
during
the
open
p~ocess
or
if
additisnal space is allocated
during
the
output
proc ess
(fi
1
e
grows),
space will not be deallocated or
the
end-of-file
pointer
updated
from
existing files
unless
the
truncate
flag and IOCMLS are explicitly set up
by
the calling program.
When
IOCMLS
is
set to the value SFFFF (value set
up d uri
n
9 . OPEN)
I
the
n'
the f i
1
e
UJ
ill
have
its
directory
entr~
deleted in
addition to having all of
its
space
deallocated
(if truncate flag
is
set
to one when. CLOSE is invoked).
rOCDBS
and
IOCDBE
must describe
a
valid
data
bUrfer
when
dealing
with
non-diskette
devices
(output
only)
since
an
end-Or-file
record
is
written (rile-type devices only>. .
A is indeterminate.
B
=
The contents of the IOCSTA entry.
If
\,
)
/
Page
25-46
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