UNW_STEP(3)						       Programming Library						       UNW_STEP(3)

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)