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/.