NAME

       unw_step -- advance to next stack frame

SYNOPSIS

       #include <libunwind.h>

       int unw_step(unw_cursor_t *cp);

DESCRIPTION

       The unw_step() routine advances the unwind cursor cp to the next older, less deeply nested stack frame.

RETURN VALUE

       On  successful  completion,  unw_step()  returns a positive value if the updated cursor refers to a valid
       stack frame, or 0 if the previous stack frame was the last frame in the chain.  On  error,  the  negative
       value of one of the error-codes below is returned.

THREAD AND SIGNAL SAFETY

       unw_step()  is  thread-safe. If cursor cp is in the local address-space, this routine is also safe to use
       from a signal handler.

ERRORS

       UNW_EUNSPEC
               An unspecified error occurred.

       UNW_ENOINFO
               Libunwind was unable to locate the unwind-info needed to complete the operation.

       UNW_EBADVERSION
               The unwind-info needed to complete the operation has a version or a format that is not understood
              by libunwind.

       UNW_EINVALIDIP
               The instruction-pointer (``program-counter'') of the next  stack  frame  is  invalid  (e.g.,  not
              properly aligned).

       UNW_EBADFRAME
               The next stack frame is invalid.

       UNW_ESTOPUNWIND
               Returned if a call to find_proc_info() returned -UNW_ESTOPUNWIND.

       In  addition, unw_step() may return any error returned by the find_proc_info(), get_dyn_info_list_addr(),
       access_mem(), access_reg(), or access_fpreg() call-backs (see unw_create_addr_space(3)).

SEE ALSO

       libunwind(3), unw_create_addr_space(3)

AUTHOR

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

Programming Library                              16 August 2007                                      UNW_STEP(3)