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UNW_INIT_LOCAL(3)            Programming Library             UNW_INIT_LOCAL(3)


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/.

Programming Library             16 August 2017               UNW_INIT_LOCAL(3)

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