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

 Message        C++ style comments (//) may not be portable.

 Description    C++ style comments have been detected on this line.
                Although they have been accepted by Compaq C in this
                language mode, they will not be accepted by all
                compilers or by Compaq C in strict C89 standard mode.

 User Action    Replace C++ style line comments (//) with equivalent
                C comments (/* ...  */) if portability is a concern.