Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!milhow1!how
From: how@milhow1.UU.NET (Mike Howard)
Newsgroups: comp.unix.xenix
Subject: SCO Compiler/Linker Problem
Message-ID: <278@milhow1.UU.NET>
Date: 5 Jan 90 19:29:46 GMT
Organization: Miller/Howard Invst., Malden-on-Hudson, NY
Lines: 129

This program (on my machine) when compiled 286 Large model creates a
variable which cannot be correctly updated.

The conditions are:
 - SCO Xenix 386, 2.3.2 with 2.3.0 development system with Beta
version of SLS #LNG085 installed.
 - 286 code.  Large model.
 - a 16 bit integer at an address ending in 0xc at the End of the data
segment.
 - On my machines (Mylex mother boards - both MQ 386 and AT 386), the
value of the variable (__argc in this case) is returned as -1, (which
I interepret as a read error).

Dumps of relavant tables:

hdr -S tst yields:
Segment table:
 type     attr      seg  filpos   psize   vsize   rbase align noff
 text    M   P     003f  0001a0  000bb4  000bb4  000000   00  0000
 data    M  B      0047  000d54  000488  0004b0  000000   00  0000
>data    M  B      004f  0011dc  000000  00a64e  000000   00  0000<<<<<
 rel      0002     0000  0011e0  000164  000000  000000   00  0000
 syms     0002     0000  001344  000418  000000  000000   00  0000
 syms     0003     0000  00175c  000467  000000  000000   00  0000
 syms     0004     0000  001bc3  00004b  000000  000000   00  0000
 syms     0005     0000  001c0e  0000a9  000000  000000   00  0000
 syms     0006     0000  001cb7  000030  000000  000000   00  0000
 syms     xseg     0000  001ce7  000734  000000  000000   00  0000

nm -n tst | tail -1 yeilds:
004f:0000a64c  B ___argc

Note that __argc is the last 16 bit address in segment 004f, which
ends 1/2 way through a 32 bit word.

Please try on various other machines and let me know what gives. 

Mike Howard
milhow1!how@uunet.uu.net or how@milhow1.uunet.uu.net

------------------------cut here for shar----------------------
#! /bin/sh
# This is a shell archive.  Remove anything before this line, then unpack
# it by saving it into a file and typing "sh file".  To overwrite existing
# files, type "sh file -c".  You can also feed this as standard input via
# unshar, or by typing "sh <file", e.g..  If this archive is complete, you
# will see the following message at the end:
#		"End of archive 1 (of 1)."
# Contents:  Makefile tst.c
# Wrapped by mike@milhow2 on Fri Jan  5 13:46:56 1990
PATH=/bin:/usr/bin:/usr/ucb ; export PATH
if test -f 'Makefile' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'Makefile'\"
else
echo shar: Extracting \"'Makefile'\" \(66 characters\)
sed "s/^X//" >'Makefile' <<'END_OF_FILE'
XCFLAGS	=	-g -Ml2 -pack
X
Xtst : tst.c
X	$(CC) $(CFLAGS) tst.c -o tst
END_OF_FILE
if test 66 -ne `wc -c <'Makefile'`; then
    echo shar: \"'Makefile'\" unpacked with wrong size!
fi
# end of 'Makefile'
fi
if test -f 'tst.c' -a "${1}" != "-c" ; then 
  echo shar: Will not clobber existing file \"'tst.c'\"
else
echo shar: Extracting \"'tst.c'\" \(393 characters\)
sed "s/^X//" >'tst.c' <<'END_OF_FILE'
Xextern int __argc;
Xchar *s1 = "this is a string";
Xchar *s2 = "this is a string";
Xchar *s3 = "this is a string";
Xchar *s4 = "this is a string";
Xchar *s5 = "this is a string";
X
Xint v1;
Xint v2;
Xint v3;
Xint v4;
Xint v5;
Xint v6;
Xint v7;
Xint v8;
Xint barfa[20000];
X
Xmain(argc, argv)
Xint argc;
Xchar **argv;
X{
X	v1 = 301;
X	v2 = 302;
X	v3 = 303;
X	v4 = 304;
X	v5 = 305;
X	v6 = 306;
X	v7 = 307;
X	__argc = v7;
X}
END_OF_FILE
if test 393 -ne `wc -c <'tst.c'`; then
    echo shar: \"'tst.c'\" unpacked with wrong size!
fi
# end of 'tst.c'
fi
echo shar: End of archive 1 \(of 1\).
cp /dev/null ark1isdone
MISSING=""
for I in 1 ; do
    if test ! -f ark${I}isdone ; then
	MISSING="${MISSING} ${I}"
    fi
done
if test "${MISSING}" = "" ; then
    echo You have the archive.
    rm -f ark[1-9]isdone
else
    echo You still need to unpack the following archives:
    echo "        " ${MISSING}
fi
##  End of shell archive.
exit 0
--------------------------end of shar---------------------------

-- 
Mike Howard
uunet!milhow1!how or milhow1!how@uunet.uu.net