Is C++ standardized?

Yes.

The C++ standard was finalized and adopted by ISO (International Organization for Standardization) as well as several national standards organizations such as INCITS (the U.S. National Committee for Information Technology Standards), BSI (the British Standards Institute), DIN (the German national standards organization). The ISO standard was finalized and adopted by unanimous vote in November 1997, with minor updates in 2003 and now significant and valuable updates in 2011. Another set of updates is expected to be published in 2014.

The U.S. C++ committee is called “PL22.16”. The ISO C++ standards group is called “WG21”. The major players in the C++ standards process have included just about everyone: representatives from Australia, Canada, Denmark, Finland, France, Germany, Ireland, Japan, the Netherlands, New Zealand, Sweden, the UK, and the USA, along with representatives from about a hundred companies and many interested individuals. Major players have included AT&T, Ericsson, Digital, Borland, Hewlett Packard, IBM, Intel, Mentor Graphics, Microsoft, NVidia, Silicon Graphics, Sun Microsystems, and Siemens.