HP-UX Reference (11i v2 04/09) - 3 Library Functions A-M (vol 6)

ManualsBrandsHP ManualsSoftwareHP-UX Reference Manuals

_UNW_getGR(3X) _UNW_getGR(3X)

(Itanium(R)-based Systems Only)

_UNW_clearAlertCode()

clears any ‘‘client needs to know’’ return code in the

_Unwind_Context

object pointed to by parameter p.

_UNW_getKernelSavedContext()

provides the means for a tool such as a kernel debugger to obtain

some of the information it needs about a kernel interruption. The values are returned via a structure of

type

_UNW_KernelSavedContext

structure from which the client can obtain the two ﬁelds,

p10_abi_value

and p10_context_value

of the format P10 unwind descriptor. For more detail,

refer to unwind(5) and to Itanium Processor Family Software Conventions and Runtime Architecture .

RETURN VALUE

Except for

_UNW_getAlertCode

, the register value query functions (which are functions with preﬁx

_UNW_get...) return the requested values on successful completion or a value equivalent to 0 other-

wise.

_UNW_getAlertCode

returns values from the enumeration _UNW_ReturnCode

. See Error condi-

tions and recovery on unwind(5).

_UNW_clear returns _UNW_OK on successful completion. Otherwise

_UNW_clear returns

_UNW_CLEAR_NOT_ALLOWED_IN_STATE

when _Unwind_Context

is not in one of the following

states: Init, User_Interrupted_Frame, User_Sendsig_Frame, Kernel_Bottom_Frame, Frame.

EXAMPLES

Tead the value of General Register 5 in this procedure frame’s context; check for range errors, query

errors, etc.; then ﬁnally clear the alert code:

#include <unwind.h>

_Unwind_Context *uc;

_UNW_ReturnCode retcode;

_UNW_GR_Value result;

uc = _UNW_createContextForSelf();

if (_UNW_OK != _UNW_currentContext(uc)) {

/* Notify client: Initialization problem */

}

else {

result=_UNW_getGR_NaT(uc,5);

switch (_UNW_getAlertCode(uc)) {

case _UNW_OK:

break;

case _UNW_QUERY_RANGE_ERROR:

/* Notify user of range error */

break;

default:

/* Notify user of other error */

break;

}

_UNW_clearAlertCode(uc);

WARNINGS

See the table in unwind(5), section CLIENT/LIBRARY INTERACTION subsection Queries, which lists

when the values returned by the query functions are guaranteed to reﬂect the actual register values of

the given procedure’s processor state. Scratch register values, for example, are valid only after crossing a

stack frame associated with an interruption. See Itanium Processor Family Software Conventions and

Runtime Architecture , Chapter 5: Register Usage.

AUTHOR

_UNW_getGR(), _UNW_getGR_NaT(), _UNW_getFR(), _UNW_getBR(), _UNW_getAR(),

_UNW_getPR(), _UNW_getPreds(), _UNW_getIP(), _UNW_getCFM(),

_UNW_getAlertCode(), _UNW_clearAlertCode(), and _UNW_getKernelSavedContext

were developed by HP.