The _U_dyn_register() routine registers unwind-info for a dynamically generated procedure. The procedure's unwind-info is described by a structure of type unw_dyn_info_t (see libunwind-dynamic(3)). A pointer to this structure is passed in argument di.
The _U_dyn_register() routine is guaranteed to execute in constant time (in the absence of contention from concurrent calls to _U_dyn_register() or _U_dyn_cancel()).
_U_dyn_register() is thread-safe but not safe to use from a signal handler.