[SR-Users] What are extended flags?

Hello, The corex module manages extended flags with functions the setxflag(), isxflagset(), and resetxflag(). tmx.t_flush_xflags() does “flush the extended flags from the current SIP message into the already created transaction. It makes sense only in routing block if the transaction was created via t_newtran() and the extended flags have been altered since. It is not needed to execute this function when using t_relay() (or similar tm relay functions, xflags are synchronized automatically in that case).” The documentation of the tm module does not say anything about extended flags - in particular it does not say that t_relay() synchronizes them. Moreover, while the corex module utilizes the extended flags, the documentation of tm and tmx do not state, that they depend on the corex module. So, what are extended flags? Greetings Дилян