The unw_set_cache_size() routine sets the cache size of address space as to hold at least as many items as given by argument size. It may hold more items as determined by the implementation. To disable caching, call unw_set_caching_policy) with a policy of UNW_CACHE_NONE. Flag is currently unused and must be 0.
On successful completion, unw_set_cache_size() returns 0. Otherwise the negative value of one of the error-codes below is returned.
unw_set_cache_size() is thread-safe but not safe to use from a signal handler.