"Richard L. Hamilton" <rlha...@smart.net> wrote: > > IMHO we should probably keep strcpy()'s behavior the > > same in this undefined case. > > It seems likely there is more code out there that > > expects the old behavior. > > It may be prudent to avoid changing "undefined" behavior in cases > where it's known that a lot of code incorrectly depends on it.
Well, my libtermcap implementation is from 1986 and at that time, the manual page for strcpy() did definitely not mention that overlapping buffers may cause problems. The oldest man page that I can find that mentions possible problems with overlapping buffers is from SunOS-4.1.1 (from 1990). Now let me ask: who reads all the man pages for all the functions that all his software uses again and again on a regular base in order to search for possible modifications that _reduce_ usability? And even iff, who remembers all assumptions he made when writing the code? > But I think it would be at least as prudent to obtain and apply tools to > identify the offending usage and fix it. Otherwise, one is simply covering > up errors; understandable for maintaining binary compatibility, but > horrible for improving quality. Reminds me of AT&T SVR[23] on the 3B15, > where behavior like /usr/lib/0...@0.so.1 provides was the default; that > let a lot of bad code keep running, but the result is that the bad code didn't > get fixed until ported to some system where that was not the default behavior. This is definitely a different issue as it is a well known fact that dereferencing null pointers will cause problems. I know that SVr3 sources for many programs did e.g. try to dereference argv[argc] and that it was a well known fact that SVr[123] did not come with cleanly written utilities. > While some degree of backwards binary compatibility with bad behavior of > other people's code may be justified, IMO it's never justified to leave such > behavior in code one has control over oneself. > > http://valgrind.org/docs/manual/mc-manual.html#mc-manual.overlap As mentioned, this is a problem that results from reducing usability of functions. The oldest man pages that I currently can find that mention overlapping buffers are from SunOS-4.1.1. BSD-4.3 does neither mention problems with strcpy() nor does it mention that bcopy() is safe for overlapping buffers. Jörg -- EMail:jo...@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin j...@cs.tu-berlin.de (uni) joerg.schill...@fokus.fraunhofer.de (work) Blog: http://schily.blogspot.com/ URL: http://cdrecord.berlios.de/private/ ftp://ftp.berlios.de/pub/schily _______________________________________________ opensolaris-code mailing list opensolaris-code@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/opensolaris-code
