Message-ID: <3AD5216F.128D108C@jps.net>
From: Dennis Yelle <dennis51 AT jps DOT net>
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Subject: Re: gdb still doesn't work for me
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Date: Wed, 11 Apr 2001 20:30:55 -0700
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To: djgpp AT delorie DOT com
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Eli Zaretskii wrote:
[...] 
> I do see that after "run", the program doesn't stop on the first
> executable line of the `main' function, which is this:
> 
>    count = 0;
> 
> Instead, it stops here:
> 
>    count += 2;
> 
> which is _after_ Paths::car7() was called.

Yes, that is another thing I have noticed several times with
different versions of gdb.  I set a breakpoint and run, and
the program either runs to completion, or stops someplace other
than the place where I put the breakpoint.  This is one of
the reasons I just concluded that gdb was unusable, and so
I didn't ever try very hard to use it.

> So I set a breakpoint on the first executable line of `main':
> 
>        (gdb) b 19
>        (gdb) run
>        (gdb) n
> 
> And _now_ it indeed runs very slowly.
> 
> The problem seems to be that GCC inlines the call to Paths::car7(),
> and that confuses GDB's "next" command.  When "next" sees a call to a
> function, it single-steps into the function over which it wants to
> step, then sets a temporary breakpoint at the return address of that
> function.  But with an inlined function, there is no return address to
> put a breakpoint on, and so GDB ends up single-stepping the whole
> region of the instructions in the inlined call.
> 
> One way to avoid this is tell GCC not to inline (with the
> "-fno-default-inline" option).  

Yes.  Thanks.  That option seems to make it work properly,
with either -g or with -gstabs.

> Another way is to not use the `n'
> command, and instead use "tb +1" and "c" commands.  The first sets a
> temporary breakpoint on the next source line, the second runs the
> program until that breakpoint.

Well, OK, so, is there a way to define a single character command that
will do the equivalent of the "tb +1" and "c" commands?
That would help me out a lot, if I could do that.

Dennis Yelle
-- 
I am a computer programmer and I am looking for a job.
There is a link to my resume here:  
http://table.jps.net/~vert/