Path: utzoo!utgpu!attcan!uunet!ginosko!aplcen!indri!uakari!csd4.milw.wisc.edu!mailrus!cornell!biar!jhood
From: jhood@biar.UUCP (John Hood)
Newsgroups: comp.unix.microport,comp.unix.i386
Subject: stop those wild NULL pointers
Summary: can it be done?
Message-ID: <788@biar.UUCP>
Date: 25 Jul 89 04:45:06 GMT
Reply-To: jhood@biar.UUCP (John Hood)
Followup-To: comp.unix.microport
Organization: Biar Games Inc., Ithaca, NY
Lines: 24


Some of you may have been watching the "NULL pointers" C language
discussion in c.u.questions.  Guy Harris mentions the -z flag to ld on
SysV for the VAX and maybe the 3B2, which maps out the first page of
memory, so that bad pointer dereferences will core-dump the program.
He talks about it as if it actually works.

I noticed this in the manual a couple of days ago, and tried it on
Microport SysV/386 3.0e.  The linker accepts this option, but won't
produce an executable.  It tells me that using '*default.bond.file*',
which I presume is generated at runtime by the linker, the bond
address for .text is not in configured memory.

Anybody know a way to get programs to compile without memory at
address 0 on a 386, without having to create a custom linker directive
file for each program?  Or is it that shared text (or maybe it's
direct page-in) make this impossible anyway?

  --jh

-- 
John Hood, Biar Games snail: 10 Spruce Lane, Ithaca NY 14850 BBS: 607 257 3423
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