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/.