unw_reg_states_iterate(3)

1UNW_REG_STATES_ITERATE(3)    Programming Library     UNW_REG_STATES_ITERATE(3)
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NAME

6       unw_reg_states_iterate -- get register state info on current procedure
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SYNOPSIS

9       #include <libunwind.h>
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11       int unw_reg_states_iterate(unw_cursor_t *cp, unw_reg_states_callbackcb,
12       void *token);
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DESCRIPTION

15       The unw_reg_states_iterate() routine  provides  information  about  the
16       procedure  that created the stack frame identified by argument cp.  The
17       cb argument is a pointer to a function of type  unw_reg_states_callback
18       which    is    used   to   return   the   information.   The   function
19       unw_reg_states_callback has the following definition:
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21       int (  *unw_reg_states_callback)(void  *token,  void  *reg_states_data,
22       size_t reg_states_data_size, unw_word_t start_ip, unw_word_t end_ip);
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24       The  callback  function  may  be invoked several times for each call of
25       unw_reg_states_iterate.  Each call is associated  with  an  instruction
26       address  range and a set of instructions on how to update register val‐
27       ues when returning from the procedure in that address range.  For  each
28       invocation, the arguments to the callback function are:
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30       void * token
31               The token value passed to unw_reg_states_callback.
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33       void * reg_states_data
34               A pointer to data about updating register values. This data, or
35              a copy of it, can be passed to unw_apply_reg_state.
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37       int reg_states_data_size
38               The size of the register update data.
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40       unw_word_t start_ip
41               The address of the first instruction of the address range.
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43       unw_word_t end_ip
44               The address of the first instruction beyond the end of the  ad‐
45              dress range.
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RETURN VALUE

48       On  successful  completion,  unw_reg_states_iterate() returns 0. If the
49       callback function returns a nonzero value, that indicates  failure  and
50       the  function  returns immediately. Otherwise the negative value of one
51       of the error-codes below is returned.
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THREAD AND SIGNAL SAFETY

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

58       UNW_EUNSPEC
59               An unspecified error occurred.
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61       UNW_ENOINFO
62               Libunwind was unable to locate unwind-info for the procedure.
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64       UNW_EBADVERSION
65               The unwind-info for the procedure has version or format that is
66              not understood by libunwind.
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68       In addition, unw_reg_states_iterate() may return any error returned  by
69       the access_mem() call-back (see unw_create_addr_space(3)).
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AUTHOR

75       David Mosberger-Tang
76       Email: dmosberger@gmail.com
77       WWW: http://www.nongnu.org/libunwind/.
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81Programming Library             29 August 2021       UNW_REG_STATES_ITERATE(3)