UNW_REG_STATES_ITERATE(3libunwind) Programming Library UNW_REG_STATES_ITERATE(3libunwind)

unw_reg_states_iterate -- get register state info on current procedure

#include <libunwind.h>

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

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 associated with an 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:


The token value passed to unw_reg_states_callback.

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

The size of the register update data.

The address of the first instruction of the address range.

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

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.

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.


An unspecified error occurred.

Libunwind was unable to locate unwind-info for the procedure.

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(3libunwind)).

libunwind(3libunwind), unw_apply_reg_state(3libunwind)

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

29 August 2023 Programming Library