HP 3000 Manuals HP 3000 Manuals
XSYSTRAP
NM and CM callable (differences noted below).
Enables or disables a user-written system trap handling procedure.
Syntax
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| |
| I*V I* |
| XSYSTRAP(plabel,oldplabel); |
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NOTE Any user trap handler cannot perform a GOTO out of that procedure.
Performing an ESCAPE (Pascal) or completing the trap handling
procedure are the only valid ways to return. The state of the
process and the program results are not predictable after a
non-local GOTO statement.
Parameters
plabel (NM) 32-bit signed integer by value (required)
(CM) 16-bit signed integer by value (required)
Passes the external-type label of the trap handling
procedure. If the value is 0, the trap handler is
disabled.
oldplabel (NM) 32-bit signed integer by reference (required)
(CM) 16-bit signed integer by reference (required)
Returns the plabel of the process's previous
software library trap handler. If no plabel was
previously configured, 0 is returned.
Operation Notes
When a program begins execution, the user-written system trap handler is
disabled automatically. When enabled by the XSYSTRAP intrinsic, and
subsequently activated by an error, the user-written system trap handler
assumes control.
The trap handler can be enabled or disabled by calling the XSYSTRAP
intrinsic.
Condition Codes
CCE (2) Request granted. Trap enabled.
CCG (0) Request granted. Trap disabled.
CCL (1) Request denied. An illegal plabel was specified.
Related Information
Intrinsics None
Commands None
Manuals Trap Handling Programmer's Guide (32650-90026)