unw_reg_states_iterate - Man Page

get register state info on current procedure

Synopsis

#include <libunwind.h>

int unw_reg_states_iterate(unw_cursor_t *cp, unw_reg_states_callbackcb, void *token);

Description

The unw_reg_states_iterate() routine provides  information about the procedure that created the stack frame  identified by argument cp. The cb argument is a pointer  to a function of type unw_reg_states_callback which is used to  return the information. The function unw_reg_states_callback has the  following definition:

int ( *unw_reg_states_callback)(void *token, void *reg_states_data, size_t reg_states_data_size, unw_word_t start_ip, unw_word_t end_ip);

The callback function may be invoked several times for each call of unw_reg_states_iterate. Each call is associcated with a instruction address range and a set of instructions on how to update register values when returning from the procedure in that address range. For each invocation, the arguments to the callback function are:

void * token

The token value passed to unw_reg_states_callback.

void * reg_states_data

A pointer to data about  updating register values. This data, or a copy of it, can be passed  to unw_apply_reg_state.

int reg_states_data_size

The size of the register update data.

unw_word_t start_ip

The address of the first  instruction of the address range.

unw_word_t end_ip

The address of the first  instruction beyond the end of the address range.

Return Value

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

Thread and Signal Safety

unw_reg_states_iterate() 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  unwind-info for the procedure.

UNW_EBADVERSION

The unwind-info for the procedure has  version or format that is not understood by libunwind.

In addition, unw_reg_states_iterate() may return any error  returned by the access_mem() call-back (see  unw_create_addr_space(3)).

See Also

libunwind(3), unw_apply_reg_state(3)

Author

David Mosberger-Tang
Email: dmosberger@gmail.com
WWW: http://www.nongnu.org/libunwind/.

Referenced By

unw_apply_reg_state(3).

16 August 2017 Programming Library