unw_init_local - Man Page

#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);

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.

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

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

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.

libunwind(3libunwind), unw_init_remote(3libunwind)

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

The man page unw_init_local2(3) is an alias of unw_init_local(3).