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From: root@hobbes.UUCP (John Plocher)
Newsgroups: comp.unix.xenix
Subject: Microport Users' Group Bug List (LONG)
Message-ID: <157@hobbes.UUCP>
Date: Thu, 23-Jul-87 14:09:55 EDT
Article-I.D.: hobbes.157
Posted: Thu Jul 23 14:09:55 1987
Date-Received: Sat, 25-Jul-87 11:55:15 EDT
References: <166@qetzal.UUCP>
Reply-To: root@hobbes.UUCP (John Plocher)
Followup-To: comp.unix.xenix
Organization: U of Wisconsin - Madison  Spanish Department
Lines: 35

+---- (Robert White) writes the following in article <166@qetzal.UUCP> ----
| 
| Compiler problems -- specifically:
| 
| 10. Passing (char *) NULL to a function in a large model program can cause
| a core dump/program abort. This makes some programs, which work under
| small model, fail under large for no apparent reason. Symptom is that
| the dump occurs between the function call and the first executable
| instruction in the function itself (usually a Mem fault or Segv)
| This blows up a LOT of things, including printf("%s", (char *) NULL)
| (or equivalent).
+----

  WRONG!  Passing the NULL pointer is not what is wrong!  What IS wrong
  is the ASSUMPTION that the data stored at location NULL is anything useful!

  printf("%s", (char *) NULL); says print the string at address 0.  This
  happens to work on a VAX because that machine SPECIFICALLY has set things
  up so that the contents of location 0 is 0.  This bad coding practice
  hits owners of Sun machines as well and is NOT a compiler bug.

+----
| 17. Along the same line, so is 'ps' with no arguments (produces nothing,
| should show your processes.) 'ps' with arguments works fine. New problem
| with 2.2.2.
+----

    Try removing the file /etc/ps_data   This will make ps work again. 
    ps_data is a cache of namelist info from /unix; when you changed
    versions, you forgot to invalidate the 'cache'.
    FLAME:  ps should check the dates on /unix and on /etc/ps_data and
    do the invalidation itself!

-- 
John Plocher uwvax!geowhiz!uwspan!plocher  plocher%uwspan.UUCP@uwvax.CS.WISC.EDU