Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (C)
Guardian Procedure Calls Reference Manual—522629-013
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CHECKPOINT Procedure
(Superseded by CHECKPOINTX Procedure )
<0:7> = 2 Takeover from primary process; then <8:15> =
0 Primary process stopped
1 Primary process abnormally ended
2 Primarys process processor failed
3 Primary process called CHECKSWITCH
<0:7> = 3 Illegal parameter; then <8:15> = number of parameter in error
(leftmost position = 1)
stack-origin input
INT:ref:*
checkpoints the process’s data stack from
stack-origin through the current tip-
of-stack location (‘S’). A checkpoint of the data stack defines a restart point for the
backup process.
buffer-n input
INT:ref:*
checkpoints a block of the process’s data area (usually a file buffer) from
buffer-
n for the number of words specified by the corresponding count-n parameter. If
you omit
buffer-n, count-n is treated as filenum and that file’s file
synchronization block is checkpointed.
count-n input
INT:value
The use of this parameter depends on the presence or absence of the
corresponding
buffer-n parameter:
•
If buffer-n is present, then count-n specifies the number of words to be
checkpointed.
•
If buffer-n is absent, then count-n is the filenum of a file whose file
synchronization block is to be checkpointed.
Considerations
•
Checkpointing the process’s data stack
The CHECKPOINT procedure provides for checkpointing the process’s data stack
and any combination of up to 13 separate data blocks and file synchronization
blocks. A data block can be from any location in the data area. (Data blocks are
usually file buffers that are not checkpointed as part of the stack, and they cannot
be in an extended data area.)
Note. If the message is too large (that is, the total of the stack size and the counts of all buffers
and the size of all file synchronization blocks is too big), status.<0:7> is set to 3 and the
parameter number is set to 26.