ckk@g.cs.cmu.edu (Chris Koenigsberg) (03/27/86)
One last data point concerning the discussion of pointers to functions..... someone mentioned that you could point to a function on a Vax, but not on a PDP-11. Since I'm one of the few non-IBM people in the world with an RT in my office, especially one running 4.2 rather than (sys V) AIX, I can add that you can't do it on an RT either, according to the following: I just got a copy of the "4.2A Linkage Convention" for the 4.2 kernel on the IBM RT PC, and I quote from page 3, under "The Data Area": "A value &foo of type pointer to function corresponds to the address of _foo, the function's data area, not the address of _.foo, the function's entry point. A program that does arithmetic on function pointers, assuming that they address entry points, will probably malfunction." Chris Koenigsberg ckk@g.cs.cmu.edu , or ckk%andrew@pt.cs.cmu.edu {harvard,seismo,topaz,ucbvax}!g.cs.cmu.edu!ckk Center for Design of Educational Computing Carnegie-Mellon U. Pgh, Pa. 15213