Guardian Procedure Calls Reference Manual

SEGMENT_ALLOCATE_CHKPT_ Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Returned Value
Considerations
Summary
The SEGMENT_ALLOCATE_CHKPT_ procedure is called by a primary process to allocate an
extended data segment for use by its backup process.
Syntax for C Programmers
This passive backup procedure is not supported in C programs. For a comparison of active backup
and passive backup, see the Guardian Programmer's Guide.
Syntax for TAL Programmers
error:= SEGMENT_ALLOCATE_CHKPT_ ( segment-id ! i
,[ filename:length ] ! i:i
,[ error-detail ] ! o
,[ pin ] ); ! i
Parameters
segment-id
input
INT:value
is the number by which the process chooses to refer to the segment. Segment IDs are in the
range of 0 to 1023 for user processes; other values are reserved for processes supplied by
HP. A nonprivileged process cannot supply a segment ID greater than 2047.
filename:length
input:input
STRING .EXT:ref:*, INT:value
indicates several types of swap files: temporary swap space using KMSF, temporary swap file,
existing permanent swap file, new permanent swap file, and segment sharing by the file-name
method.
If filename is specified, pin must be omitted.
• Temporary swap space using KMSF
If you do not specify filename or if you specify length as 0 (and if a segment is not
being shared using the PIN method), SEGMENT_ALLOCATE_CHKPT_ uses the
Kernel-Managed Swap Facility (KMSF) to allocate swap space.
To share this segment, use the PIN method; you cannot use the file-name method.
Performance is increased by using KMSF. However, if you want to save the data in the
segment after the process terminates, specify a permanent swap file name. KMSF swap
files have the clear-on-purge attribute, which provides a level of security for swapped data.
1272 Guardian Procedure Calls (S)