VMS Help POSIX Threads, PTHREAD routines, pthread_key_getname_np, Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    This routine copies the object name from the thread-specific
    data key object specified by the key argument to the buffer at
    the location specified by the name argument. Before calling this
    routine, your program must allocate the buffer indicated by name.

    The object name is a C language string and provides an identifier
    that is meaningful to a person debugging a multithreaded
    application. The maximum number of characters in the object name
    is 31.

    If the specified thread-specific data key object has not been
    previously set with an object name, this routine copies a C
    language null string into the buffer at location name.