Plwp_stack,
Plwp_alt_stack,
Plwp_main_stack,
Lstack,
Lalt_stack,
Lmain_stack —
get thread stack information
Process Control Library (libproc, -lproc)
#include
<libproc.h>
int
Plwp_stack(
struct
ps_prochandle *P,
lwpid_t lwpid,
stack_t *stkp);
int
Plwp_alt_stack(
struct
ps_prochandle *P,
lwpid_t lwpid,
stack_t *stkp);
int
Plwp_main_stack(
struct
ps_prochandle *P,
lwpid_t lwpid,
stack_t *stkp);
int
Lalt_stack(
struct
ps_lwphandle *L,
stack_t *stkp);
int
Lmain_stack(
struct
ps_lwphandle *L,
stack_t *stkp);
int
Lstack(
struct
ps_lwphandle *L,
stack_t *stkp);
The
Plwp_stack(),
Plwp_alt_stack(), and
Plwp_main_stack() functions obtain
information about the size and address of the stacks for the thread identified
by
lwpid in the process handle
P.
Each thread in a process has its own stack which is used both for maintaining
function call sequences and the storing of local variables. A thread may also
configure a different stack to handle specific signals. This stack is often
called the
alternate stack. Whether or not the
alternate stack is used may be controlled through the
sigaction(2) and
sigaltstack(2) functions .
The
Plwp_stack() function fills in
stkp with the information about the thread's
currently executing stack, whether the alternate or main one.
The
Plwp_alt_stack() function fills in
stkp with the information about the thread's
alternate stack, if it's configured.
The
Plwp_main_stack() function fills in
stkp with the information about the thread's
main stack, regardless of if there is an alternate stack or it is executing
one.
Process handles that refer to files, obtained through
Pgrab_file(3PROC), do not have any stack
information and these functions will always fail on them.
The
Lalt_stack(),
Lmain_stack(), and
Lstack() functions are identical to the
Plwp_alt_stack(),
Plwp_main_stack(), and
Plwp_main_stack() functions, except rather
than specifying a thread to operate on, they operate on the thread handle
L, which specifies the thread to operate on.
Upon successful completion, the
Plwp_stack(),
Plwp_alt_stack(),
Plwp_main_stack(),
Lalt_stack(),
Lmain_stack(), and
Lstack() functions return
0 and fills in
stkp with information about the appropriate
stack. Otherwise,
-1 is returned,
errno is updated with the error, and
stkp is not modified.
For a full list of possible errors also see the
DIAGNOSTICS section in
proc(4).
The
Plwp_stack(),
Plwp_alt_stack(), and
Plwp_main_stack() function will fail if:
-
-
ENODATA- The process handle P refers to a grabbed
file, not an active process or core.
-
-
EINVAL- The process handle P refers to a core
file and the specified thread does not exist.
-
-
ENOENT- The process handle P refers to an active
process and the specified thread does not exist.
The
Plwp_alt_stack() and
Lalt_stack() functions will fail if:
-
-
ENODATA- The thread identified by lwpid did not
have an alternate stack enabled.
Uncommitted
See
LOCKING in
libproc(3LIB).
sigaction(2),
sigaltstack(2),
libproc(3LIB),
proc(4)