Tom Duff himself writes about it here: http://doc.cat-v.org/bell_labs/duffs_device http://doc.cat-v.org/bell_labs/duffs_device In particular, The device

Tom Duff himself writes about it here: http://doc.cat-v.org/bell_labs/duffs_device http://doc.cat-v.org/bell_labs/duffs_device In particular, The device is legal dpANS C. I cannot quote chapter and verse, but Larry Rosler, who was chairman of the language subcommittee (I think), has assured me that X3J11 considered it carefully and decided that it was legal. Somewhere I have a note from dmr certifying that all the compilers that he believes in accept it. Of course, the device is also legal C++, since Bjarne uses it in his book.