UNW_STEP(3) Programming Library UNW_STEP(3)NAMEunw_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 SAFETYunw_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 com‐
plete 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_ESTOPUN‐
WIND.
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 ALSOlibunwind(3), unw_create_addr_space(3)AUTHOR
David Mosberger-Tang
Hewlett-Packard Labs
Palo-Alto, CA 94304
Email: davidm@hpl.hp.com
WWW: http://www.hpl.hp.com/research/linux/libunwind/.
Programming Library 05 August 2004 UNW_STEP(3)
