unw_step(3)

1UNW_STEP(3)                  Programming Library                   UNW_STEP(3)
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NAME

6       unw_step -- advance to next stack frame
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SYNOPSIS

9       #include <libunwind.h>
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11       int unw_step(unw_cursor_t *cp);
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DESCRIPTION

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

18       On successful completion, unw_step() returns a positive  value  if  the
19       updated  cursor  refers  to  a  valid stack frame, or 0 if the previous
20       stack frame was the last frame in the chain.  On  error,  the  negative
21       value of one of the error-codes below is returned.
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THREAD AND SIGNAL SAFETY

24       unw_step()  is thread-safe. If cursor cp is in the local address-space,
25       this routine is also safe to use from a signal handler.
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ERRORS

28       UNW_EUNSPEC
29               An unspecified error occurred.
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31       UNW_ENOINFO
32               Libunwind was unable to locate the unwind-info needed  to  com‐
33              plete the operation.
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35       UNW_EBADVERSION
36               The  unwind-info needed to complete the operation has a version
37              or a format that is not understood by libunwind.
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39       UNW_EINVALIDIP
40               The instruction-pointer (``program-counter'') of the next stack
41              frame is invalid (e.g., not properly aligned).
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43       UNW_EBADFRAME
44               The next stack frame is invalid.
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46       UNW_ESTOPUNWIND
47               Returned  if  a call to find_proc_info() returned -UNW_ESTOPUN‐
48              WIND.
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50       In  addition,  unw_step()  may  return  any  error  returned   by   the
51       find_proc_info(), get_dyn_info_list_addr(), access_mem(), access_reg(),
52       or access_fpreg() call-backs (see unw_create_addr_space(3)).
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AUTHOR

58       David Mosberger-Tang
59       Hewlett-Packard Labs
60       Palo-Alto, CA 94304
61       Email: davidm@hpl.hp.com
62       WWW: http://www.hpl.hp.com/research/linux/libunwind/.
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66Programming Library             05 August 2004                     UNW_STEP(3)