VMS Help CC, Messages, C99NAONVAX  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Message        Full C99 is not supported on this platform.  Language
                mode set to "relaxed_ansi89", which includes the C99
                features supported on this platform.

 Description    The Compaq C compiler on OpenVMS VAX does not support
                the C99 standard and will therefore not accept the
                /STANDARD=C99 qualifier.  The compiler will use
                /STANDARD=RELAXED_ANSI.  This mode includes all C99
                features that are supported on OpenVMS VAX.

 User Action    Do not use /STANDARD=C99 on this platform.