backtrace C-API

backtrace C-API

[Gerrit Bruchhäuser]

Hello,

is there any C-API function in libgdb.a (or some other library) which
returns a call stack (something 'bt' like)?

Many thanks!
// Gerrit

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Re: backtrace C-API

[Daniel Jacobowitz]

On Fri, Apr 18, 2003 at 02:33:27PM +0200, Gerrit Bruchhäuser wrote:
> Hello,
> 
> is there any C-API function in libgdb.a (or some other library) which
> returns a call stack (something 'bt' like)?

No; but you might find backtrace() useful if you're on a
glibc-supported platform.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: backtrace C-API

[Andrew Cagney]

> On Fri, Apr 18, 2003 at 02:33:27PM +0200, Gerrit Bruchhäuser wrote:
> 
>> Hello,
>> 
>> is there any C-API function in libgdb.a (or some other library) which
>> returns a call stack (something 'bt' like)?
> 
> 
> No; but you might find backtrace() useful if you're on a
> glibc-supported platform.

But there probably should.  How hard is it to create a `target-self' 
that uses local memory, and a jump-buf for registers?  The tricky bit, I 
see, is the symbol table assuming a single global structure.

Andrew

Re: backtrace C-API

[Jason Molenda]

On Monday, April 21, 2003, at 02:04  PM, Andrew Cagney wrote:

>> On Fri, Apr 18, 2003 at 02:33:27PM +0200, Gerrit Bruchhäuser wrote:
>>> Hello,
>>> is there any C-API function in libgdb.a (or some other library) which
>>> returns a call stack (something 'bt' like)?
>> No; but you might find backtrace() useful if you're on a
>> glibc-supported platform.
>
> But there probably should.  How hard is it to create a `target-self' 
> that uses local memory, and a jump-buf for registers?  The tricky bit, 
> I see, is the symbol table assuming a single global structure.


This falls into the category of Nasty Hack, but I helped someone on our 
compiler group with a similar problem a long time ago.  I had them add 
a call at the site of interest which (a) got the current process' pid, 
(b) wrote a little gdb command script into a /tmp file which would 
attach to the process, bt, and detach, (c) ran system ("gdb 
--command=/tmp...") in the function, and (d) removed the file from /tmp.

I'm sure there are better ways to handle all this, but it took about 
five minutes to do all this correctly -- for a one-off problem, it 
wasn't a bad solution.  They captured stdout, massaged the output a 
bit, and had the info they needed.

J

Re: backtrace C-API

[Andrew Cagney]

> 
> On Monday, April 21, 2003, at 02:04  PM, Andrew Cagney wrote:
> 
> On Fri, Apr 18, 2003 at 02:33:27PM +0200, Gerrit Bruchhäuser wrote:
> Hello,
> is there any C-API function in libgdb.a (or some other library) which
> returns a call stack (something 'bt' like)?
> No; but you might find backtrace() useful if you're on a
> glibc-supported platform.
> 
> But there probably should.  How hard is it to create a `target-self' that uses local memory, and a jump-buf for registers?  The tricky bit, I see, is the symbol table assuming a single global structure.
> 
> 
> This falls into the category of Nasty Hack, but I helped someone on our compiler group with a similar problem a long time ago.  I had them add a call at the site of interest which (a) got the current process' pid, (b) wrote a little gdb command script into a /tmp file which would attach to the process, bt, and detach, (c) ran system ("gdb --command=/tmp...") in the function, and (d) removed the file from /tmp.
> 
> I'm sure there are better ways to handle all this, but it took about five minutes to do all this correctly -- for a one-off problem, it wasn't a bad solution.  They captured stdout, massaged the output a bit, and had the info they needed.

It's actually a well accepted technique.  I first learnt about it on a 
web page somewhere.

Andrew