From:	Ian D Romanick <idr AT cs DOT pdx DOT edu>
Message-Id:	<199709101508.IAA22966@sirius.cs.pdx.edu>
Subject:	Re: SIGSEGV error meanings??
To:	me AT jenkinsdavid DOT demon DOT co DOT uk (David Jenkins)
Date:	Wed, 10 Sep 1997 08:08:20 -0700 (PDT)
Cc:	djgpp AT delorie DOT com
In-Reply-To:	<$pUtJBAbyoF0EwFX@jenkinsdavid.demon.co.uk> from "David Jenkins" at Sep 10, 97 01:03:39 pm
MIME-Version:	1.0

> G:\Hoveroids\code\Game>symify -i bug1.txt hover.exe
> Shutting down Allegro
> Exiting due to signal SIGSEGV
> Page fault at eip=000056ba, error=0004
> eax=69696b6a ebx=0002a7e4 ecx=00b68004 edx=00000000 esi=69696b6a
> edi=0089d470
> ebp=ff465f20 esp=ff465ef8 program=C:\MYFILES\TEMP\HOVER.EXE
> cs: sel=00a7  base=845b6000  limit=ff465fff
> ds: sel=00af  base=845b6000  limit=ff465fff
> es: sel=00af  base=845b6000  limit=ff465fff
> fs: sel=00af  base=845b6000  limit=ff465fff
> gs: sel=00c7  base=00000000  limit=ffffffff
> ss: sel=00af  base=845b6000  limit=ff465fff
> 
> Call frame traceback EIPs:
>   0x000056ba __getpixel+30
>   0x000036be _make_hover_sprites+174, line 300 of init.c
>   0x00002de7 _init_display+259, line 72 of init.c
>   0x00003cf2 _main+82, line 41 of main.c
>   0x0003456e ___crt1_startup+138
> 
> the , line 300 of init.c are pretty straightforward.
> BUT what's the +174 in _make_hover_sprites+174 mean??

It means the symbol _make_hover_sprites (the start of that funcion) plus 174
bytes.  The program is actually crashing 30 bytes into _getpixel().  Since
%edx contains NULL, you probably passed that function a bum pointer.

> AND What's this ___crt1_startup+138, and where did it come from?? Is it
> something in the startup code or something??

Correctamundo!

-- 
"Harshaw conceded that man, a social animal, could not avoid government, any
more than an individual could escape bondage to his bowels." 
                                               -- Stranger In A Strange Land
See my bowels at http://www.cs.pdx.edu/~idr

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