Guardian Procedure Calls Reference Manual (G06.25+)

Guardian Procedure Calls (C)
Guardian Procedure Calls Reference Manual—522629-013
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CHECKMONITOR Procedure
CHECKMONITOR Procedure
Summary
Syntax for C Programmers
Syntax for TAL Programmers
Parameters
Considerations
Messages
Summary
The CHECKMONITOR procedure is called by a backup process to monitor the state of
the primary process and to return control to the appropriate point (in the backup
process) in the event of a failure of the primary process.
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
Parameters
status returned value
INT
returns a status word of the following form:
<0:7> = 2
<8:15> = 0 Primary process stopped
1 Primary process abnormally ended
2 Primarys porcess processor failed
3 Primary process called CHECKSWITCH
status := CHECKMONITOR;
Note. The normal return from a call to CHECKMONITOR is to the statement following a call to
the CHECKPOINT[MANY][X] procedure. The return corresponds to the latest call to
CHECKPOINT[MANY][X] by the primary process in which its stack was checkpointed.
The backup process executes the statement following the call to CHECKMONITOR only if the
primary process has not checkpointed its stack through a call to the CHECKPOINT[MANY][X]
procedure.