unw_step - Man Page

#include <libunwind.h>

int unw_step(unw_cursor_t *cp);

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

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.

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.

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(3libunwind)).

libunwind(3libunwind), unw_create_addr_space(3libunwind)

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