/sys$common/syshlp/helplib.hlb CC, Messages, BADANSIALIAS  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        This statement uses the type "<type>" to reference
                the same storage location as the statement at <loc>,
                which uses the type "<type>".  This does not conform
                to the ANSI aliasing rules.

 Description    The standard allows a compiler to assume that since
                these two statements use different types, these two
                statements reference different storage locations.
                The Compaq C compiler does so whenever ansi aliasing
                is enabled.  Since your code relies on these two
                statements referencing the same storage location you
                should disable ansi aliasing.  If you do not do so,
                optimization may result in your program exhibiting
                unexpected behavior.

 User Action    Specify noansi_alias on the command line.