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

    This routine produces a text message on the stderr device
    (Tru64 UNIX systems) or SYS$ERROR device (OpenVMS systems) that
    describes the exception whose exception object is specified in
    the exception argument.

    In a program that uses status exceptions, use this routine within
    a CATCH or CATCH_ALL code block to produce the message associated
    with a caught exception. Note that any exception objects set to
    the same status value are considered equivalent by the Threads
    Library.