Guardian Procedure Calls Reference Manual

In addition, the displayed context is affected when any combination of these bits are set to 1:
HO_NoSuppress<11>
enables the display of transition frames, including the shells by which TNS code calls native
procedures, the system procedure that calls a signal handler, and some transitions within
low-level system software. By default, transition frames are not displayed.
HO_ShowProtected<10>
enables the display of protected context when a signal is generated within protected code. If
a signal is generated within protected code, such as in a procedure running privileged, the
context at that site is preserved in the uContext structure passed to the signal handler, but it is
not displayed unless this option is set.
HO_OneLine<7>
modifies some formatting options to optimize the display of information in a single output line.
It does not, however, ensure that all the information fits in one line.
context
input
EXTADDR:value
designates the procedure context for display. The type of context whose address appears in
context must match the context type specified in the options parameter bits <13:15> (the
HO_Init_* value) as follows:
Then context must point to...If options.<13:15> specifies...
Anything (it is ignored)HO_Init_Here (0)
A uContext structureHO_Init_uContext (1)
A jump bufferHO_Init_JmpBuf (2)
A code addressHO_Init_Address (4)
Returned Value
INT
Outcome of the call:
HIST_OK0
The procedure terminated normally.
HIST_DONE1
The procedure has reached the base of the stack trace.
HIST_BAD_VERSION-3
An invalid value was specified for the version parameter.
HIST_BAD_OPTION-4
An invalid value was specified for the options parameter. An undefined bit was set.
HIST_BAD_CONTEXT-5
A null value was specified for the context parameter. The context parameter must contain an address.
HIST_NOT_IMPLEMENTED-6
A specified options bit is defined but not implemented.
HIST_INIT_ERROR-7
An error occurred during an attempt to initialize the stack trace.
HIST_ERROR-8
718 Guardian Procedure Calls (H-K)