Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (C)
Guardian Procedure Calls Reference Manual—522629-013
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CHECKPOINTX Procedure
CHECKPOINTX Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Considerations
Summary
The CHECKPOINTX procedure (like the CHECKPOINTMANYX procedure) is called by
a primary process to send information about its current executing state to its backup
process. The checkpoint information enables the backup process to recover from a
failure of the primary process in an orderly manner. The backup process must be in
the “monitor” state (that is, in a call to the CHECKMONITOR procedure) for the
CHECKPOINTX call to be successful.
This procedure can be used to checkpoint:
•
Stack data from a specified stack address to the tip of the stack
•
Up to five data areas
•
File synchronization blocks
The CHECKPOINTX procedure can be used by both TNS processes and native
processes. It allows checkpointing of data in extended data segments (flat or
selectable) in addition to the user data segment.
Use the CHECKPOINTMANYX procedure if you need to checkpoint more than five
data areas.
Syntax for C Programmers
This passive backup procedure is not supported in C programs. For a comparison of
active backup and passive backup, refer to the
Guardian Programmer’s Guide.
Syntax for TAL Programmers
status := CHECKPOINTX ( [ stack-origin ] ! i
,[ segment-id1 ], [ bufferx-1 ], [ count-1 ] ! i,i,i
,[ segment-id2 ], [ bufferx-2 ], [ count-2 ] ! i,i,i
. .
. .
. .
,[ segment-id5 ], [ bufferx-5 ], [ count-5 ] ); ! i,i,i