catch throw -how?

catch throw -how?

[Markus Werle]

Hi!

Using gdb-5.1.1 I wanted to use the "catch" feature for C++ exceptions like this

# gdb ./myprogram
GNU gdb 5.1.1
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...
(gdb) catch throw
You can't do that without a process to debug.
(gdb)

1. I do not understand the error message, please explain
2. Is this a bug resolved in gdb-5.3 or am I missing some information?


best regards,


Markus

Re: catch throw -how?

[Daniel Jacobowitz]

On Tue, Jan 28, 2003 at 04:35:14PM +0100, Markus Werle wrote:
> Hi!
> 
> Using gdb-5.1.1 I wanted to use the "catch" feature for C++ exceptions like this
> 
> # gdb ./myprogram
> GNU gdb 5.1.1
> Copyright 2002 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
> welcome to change it and/or distribute copies of it under certain conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB.  Type "show warranty" for details.
> This GDB was configured as "i686-pc-linux-gnu"...
> (gdb) catch throw
> You can't do that without a process to debug.
> (gdb)
> 
> 1. I do not understand the error message, please explain
> 2. Is this a bug resolved in gdb-5.3 or am I missing some information?

I don't think that "catch throw" works on any GNU/Linux target right
now.  I've got it about half re-implemented for GCC 3.x in a scratch
directory right now but I don't know when I'm going to have time to
test it.

You can get just about the same effect in GCC 3.x by putting a
breakpoint on __cxa_throw.  In 2.x I think it was __throw.

-- 
Daniel Jacobowitz
MontaVista Software                         Debian GNU/Linux Developer

Re: catch throw -how?

[Bennett F. Dill]

On Tue, Jan 28, 2003 at 04:35:14PM +0100, Markus Werle wrote:
> Hi!
> 
> Using gdb-5.1.1 I wanted to use the "catch" feature for C++ exceptions like this
> 
> # gdb ./myprogram
> GNU gdb 5.1.1
> Copyright 2002 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
> welcome to change it and/or distribute copies of it under certain conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB.  Type "show warranty" for details.
> This GDB was configured as "i686-pc-linux-gnu"...
> (gdb) catch throw
> You can't do that without a process to debug.
> (gdb)
> 
> 1. I do not understand the error message, please explain
> 2. Is this a bug resolved in gdb-5.3 or am I missing some information?
> 
> 
> best regards,
> 
> 
> Markus
> 
Markus,

I'm not sure, but i think you may need to specify a core file at
startup, or attach to a process that you want to debug...

process id of program to debug = 4128
user@host:~$ gdb
(gdb) attach 4128
Attaching to process 4128
Reading symbols from /usr/lib/libcurses.so.1...(no debugging symbols found)...
done.
Reading symbols from /usr/lib/libc.so.1...(no debugging symbols found)...done.
Reading symbols from /usr/lib/libdl.so.1...(no debugging symbols found)...done.
Reading symbols from /usr/platform/SUNW,Ultra-1/lib/libc_psr.so.1...  (no debugging symbols found)...done.
Symbols already loaded for /usr/lib/libcurses.so.1
Symbols already loaded for /usr/lib/libc.so.1
Symbols already loaded for /usr/lib/libdl.so.1
Symbols already loaded for /usr/platform/SUNW,Ultra-1/lib/libc_psr.so.1
0xff319ad4 in syscall () from /usr/lib/libc.so.1
(gdb)

now try your catch...  I'm not sure if that helps or not, but good luck
:-)

Ben

Re: catch throw -how?

[Markus Werle]

Daniel Jacobowitz wrote:

> You can get just about the same effect in GCC 3.x by putting a
> breakpoint on __cxa_throw.

Bingo!
Many, many thanks for this hint.


best regards,


Markus