setjmp(3c) et. al. don't discuss usage with threads
The only mention of using setjmp(3c), etc. with threads in their man page is in the attributes table where the functions are listed as MT-unsafe. While technically correct, it is permissible to use setjmp/longjmp/etc. within a thread as long as the jmp_buf is created and used in the same thread. This should probably be added (with better wording) to the man page.