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From: dc@datlog.co.uk ( David Crone )
Newsgroups: net.micro.att,net.unix
Subject: Re: Cannot set breakpoint with 'sdb' on 3b2
Message-ID: <563@dlvax1.datlog.co.uk>
Date: Wed, 2-Apr-86 04:32:12 EST
Article-I.D.: dlvax1.563
Posted: Wed Apr  2 04:32:12 1986
Date-Received: Sat, 5-Apr-86 07:57:39 EST
References: <424@chinet.UUCP>
Reply-To: dc@datlog.co.uk ( David Crone )
Organization: Data Logic Ltd, Queens House, Greenhill Way, Harrow, London.
Lines: 39
Xref: linus net.micro.att:1093 net.unix:6911

In article <424@chinet.UUCP> djc@chinet.UUCP (David J. Carpenter) writes:
>I have been using the sdb debugger on some software that I have been 
>developing, and one day a problem appeared and has stayed ever since.  I cannot
>set a breakpoint and then run the program.  Here's what I get:
>
>--> sdb /usr/local/bin/prog   [source in current dir]
>No core image.
>*
>--> main:b	[or any breakpoint...]
>0x80800116 (main:26+2) b
>*
>--> r arg
>Cannot set breakpoint: main:1 @ -2139094762
>[and then the program runs without stopping at main...]
>
>
>Anyone know what is going wrong here?   Thanks...
>-- 
>					...!ihnp4!ttrdc!exp747!qpsn!david
>					David Carpenter
>					[home] (312) 545-8076
>					[work] (312) 787-9343

A similar thing happens using 'adb' and the cause is that the program that is
being debugged is already being run by someone else. As the default link option
is to share process text then the debugger shares the text segment of the
already running process. Because of this the debugger won't set your breakpoint
and hence doesn't stop at main.

Two ways round this:
		i) Link the required process as non-shared text.
        or     ii) Make your own copy of the process (different name)
		   and debug that.

(caveat: This has happened to me on a number of machines, however I have no
 	 direct experience of using a 3b2, so minimum flames please)
	
	Hope this helps,
			David Crone