unw_step −− advance to next stack frame
#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(3)).
libunwind(3), unw_create_addr_space(3)
David
Mosberger−Tang
Email: [email protected]
WWW: http://www.nongnu.org/libunwind/.