VMS Help POSIX Threads, TIS routines, tis_setspecific, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 key

    Thread-specific data key that identifies the data to receive
    value. Must be obtained from a call to tis_key_create().

 value

    New value to associate with the specified key. Once set, this
    value can be retrieved using the same key in a call to tis_
    getspecific().