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

 Message        <Context> "<name>" does not have a constant address,
                but occurs in a context that requires an address
                constant.  This is an extension of the language.

 Description    The C89 standard requires that an initializer for a
                pointer-type member of an automatic aggregate or
                union-type object have an initializer that is an
                address constant.  Other C compilers might not
                successfully compile a program that uses this
                extension.

 User Action    Be aware of this if you wish to port the program.