How to step into multi-command statements

How to step into multi-command statements

[Tron Thomas]

If I were debugging a program and ran across code like the following:

string text;
...
formatter.DisplayText(text.c_str());

What commands do I use to step into the DisplayText method of the 
formatter object?  Stepping into the statement takes me into the code 
for the c_str method of the string class, which I don't care about.  
After getting into this code I'm finding it impossible to get into the 
actual code I want.  Instead I end up being going to the next statement 
that follows the call to DisplayText.

Re: How to step into multi-command statements

[Bob Rossi]

On Sat, Aug 21, 2004 at 10:30:25AM -0700, Tron Thomas wrote:
> If I were debugging a program and ran across code like the following:
> 
> string text;
> ...
> formatter.DisplayText(text.c_str());
> 
> What commands do I use to step into the DisplayText method of the 
> formatter object?  Stepping into the statement takes me into the code 
> for the c_str method of the string class, which I don't care about.  
> After getting into this code I'm finding it impossible to get into the 
> actual code I want.  Instead I end up being going to the next statement 
> that follows the call to DisplayText.

You need to 'step', 'finish', 'step', 'finish', until you get to the
function that you want.

Bob Rossi

Re: How to step into multi-command statements

[Joel Brobecker]

> You need to 'step', 'finish', 'step', 'finish', until you get to the
> function that you want.

Funny. One of our users actually asked for an enhancement to implement
a function that would do a step-last, ie step into the last function
being called in the line of code. For instance, given the following 
code:

         Foo (A, Bar (B));

steplast would land inside Foo, not Bar.

The premise for this request was that WDB, the HP/UX debugger, was
implementing it.

I looked at HP's implementation, and they were basically using two
approaches, as far as I can remember:
  - heuristics, knowing how calls where implemented on their target
    (this is for older versions of their compiler)
  - debug info, generated by their recent compiler.

We are still not exactly sure that this would be very useful
enhancement, especially if we don't get any help from the compiler
as the HP compiler does. Right now, our position is that it is easy
to write a user-command that does something close:

         define stepfunc
             tbreak $arg0
             cont
         end

With the function above, it's not entirely automatic, as you have
to give the name of the function you want to step in, but it is also
more flexible, as you can step into the function you want, it doesn't
have to be the last function called.

Food for thoughts...

-- 
Joel

Re: How to step into multi-command statements

[Andrew Cagney]

> If I were debugging a program and ran across code like the following:
> 
> string text;
> ...
> formatter.DisplayText(text.c_str());
> 
> What commands do I use to step into the DisplayText method of the formatter object?  Stepping into the statement takes me into the code for the c_str method of the string class, which I don't care about.  After getting into this code I'm finding it impossible to get into the actual code I want.  Instead I end up being going to the next statement that follows the call to DisplayText. 

Try:

(gdb) advance formatter.DisplayText

Andrew