Open - Control Data Corporation 3300 Reference Manual

4.7.16
OPEN
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The OPEN statement initiates the processing of both input and output files.
It performs checking and/or writing of labels and other input-output operations.
INPUT file-name-l
[l!~:~~EWINDi
] [.
file-name-2
[l
~;:~~EWIND
!Jl· .
OPEN OUTPUT file-name-l [WITH NO REWIND]
[, file-name-2 [WITH NO REWIND]]
1-0
file-name-l [, file-name-2] ...
INPUT-OUTPUT file-narne-l [, file-name-2] ...
At least one of the options INPUT, OUTPUT,
1-0
must be specified; however,
there should be no more than one instance of each option per statement. These
options may appear in any order. The 1-0 and INPUT-OUTPUT options per-
tain only to mass storage files.
All files except sort files must be opened with an OPEN statement prior
to
execution of the first SEEK, READ, WRITE or CLOSE statement for that file.
Sort files must not be named in an OPEN statement. OPEN does not obtain
or release the first data record; a READ must be executed
to
obtain, or a
WRITE to release the first data record. A second OPEN statement for a file
cannot be executed prior to the execution of a CLOSE statement for that file.
The user's beginning label subroutine is executed for checking or writing the
first label if one is specified by a USE statement.
The REVERSED and NO REWIND options can be used only with sequential
single-reel files; they do not apply to mass storage processing. If the external
device permits rewinding, and if REVERSED or NO REWIND are not specified,
execution of the OPEN statement positions the file at its beginning.
If either REVERSED or NO REWIND is specified, the file is not repositioned.
REVERSED assumes the file is positioned at its end; NO REWIND assumes
the file is positioned at its beginning.
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