NAME

       unw_init_local -- initialize cursor for local unwinding

SYNOPSIS

       #include <libunwind.h>

       int unw_init_local(unw_cursor_t *c, unw_context_t *ctxt);
       int unw_init_local2(unw_cursor_t *c, unw_context_t *ctxt, int flag);

DESCRIPTION

       The  unw_init_local()  routine  initializes  the  unwind  cursor  pointed to by c with the
       machine-state in the context structure pointed to by ctxt.   As  such,  the  machine-state
       pointed  to  by  ctxt  identifies  the  initial stack frame at which unwinding starts. The
       machine-state is expected to be one provided by a call to  unw_getcontext;  as  such,  the
       instruction pointer may point to the instruction after the last instruction of a function,
       and libunwind will back-up the instruction pointer before beginning a  walk  up  the  call
       stack.  The  machine-state must remain valid for the duration for which the cursor c is in
       use.

       The unw_init_local() routine can be used only for unwinding in the address  space  of  the
       current  process (i.e., for local unwinding).  For all other cases, unw_init_remote() must
       be used instead.  However, unwind performance may be better when  using  unw_init_local().
       Also,  unw_init_local()  is  available  even  when  UNW_LOCAL_ONLY has been defined before
       including <libunwind.h>, whereas unw_init_remote() is not.

       If the unw_context_t is known to be a signal frame (i.e., from the  third  argument  in  a
       sigaction  handler  on linux), unw_init_local2() should be used for correct initialization
       on some platforms, passing the UNW_INIT_SIGNAL_FRAME flag.

RETURN VALUE

       On successful completion, unw_init_local() returns 0.  Otherwise the negative value of one
       of the error-codes below is returned.

THREAD AND SIGNAL SAFETY

       unw_init_local() is thread-safe as well as safe to use from a signal handler.

ERRORS

       UNW_EINVAL
               unw_init_local()  was  called  in  a  version  of  libunwind which supports remote
              unwinding  only  (this  normally  happens  when  calling  unw_init_local()  for   a
              cross-platform version of libunwind).

       UNW_EUNSPEC
               An unspecified error occurred.

       UNW_EBADREG
               A register needed by unw_init_local() wasn't accessible.

SEE ALSO

       libunwind(3), unw_init_remote(3)

AUTHOR

       David Mosberger-Tang
       Email: dmosberger@gmail.com
       WWW: http://www.nongnu.org/libunwind/.