Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (O)
Guardian Procedure Calls Reference Manual—522629-013
11-17
OPEN Procedure (Superseded by FILE_OPEN_
Procedure )
primary-process-id and primary-filenum are supplied only if the open is
by the backup process of a process pair, the file is currently open by the primary
process,
and the checkpointing facility is not used. Both parameters must be
supplied.
seq-block-buffer-id input
INT:ref:1
is a 16-bit value, the address of which identifies the sequential block buffer to be
shared, if sequential block buffering is used and if sharing is desired. If sharing is
not desired, this parameter can be omitted since all sequential buffers will reside in
the process’s PFS with the size given by
buffer-length. All opens giving this
ID share the same sequential block buffer. Any integer value can be supplied for
this parameter.
If sequential block buffering is used, the file should usually be opened with
protected or exclusive access. Shared access can be used, although there are
potential concurrency problems, and it is somewhat slower than other access
methods in the case of key-sequenced files. Refer to the discussion of “Sequential
Block Buffering” in the
Enscribe Programmer’s Guide.
buffer-length input
INT:value
is the length in bytes of the sequential block buffer. This is the only parameter that
is required for the sequential block buffering option to be in effect when buffer
sharing is not used.
If the
buffer-length is less than the data-blocklen specified in the creation
of this file or any associated alternate-key files, then the larger size is used, unless
a buffer that was established by an earlier call to OPEN is being shared and is too
small. In that case OPEN succeeds but returns a CCG indication (a subsequent
call to FILEINFO or FILE_GETINFO_ shows that an error 5 occurred). Normal
system buffering is then used instead of the application process’s sequential buffer.
If this parameter is omitted, sequential block buffering is not attempted.
primary-define input
INT:ref:12
specifies the name of the DEFINE which was used as the
file-name in the open
of the primary process. (In the backup,
file-name must be the actual name of
the file.) The DEFINE must exist and must have the same value as it did when the
primary open was made. This parameter is relevant only for a process pair which
does not use the CHECKOPEN or CHECKMONITOR procedures.
The
primary-define parameter should be supplied only if this open is a backup
open and the primary open was made using a DEFINE.