I had built PJSIP 2.7.1 and was integrating it for an iOS app written in Swift. Everything worked so I believed it was built the right way, all libs and headers were in the right place too, until one day I was trying to call lib functions from an external thread so I registered this thread by using "pj_thread_register()" and declared a "pj_thread_t" type variable, the compiler started to complain about that the type "pj_thread_t" was undeclared. I found the "pj_thread_t" was declared in "pj/types.h" and was defined in "pj/os_core_linux_kernel.c". The "types.h" was already included in the header search path and I supposed it should work. I guess I must have missed something here. Someone please give me a hint, appreciated! -zhe