RE: Finding the type of an exception

["Kulkarni, Mayuresh \(IT\)" <Mayuresh dot Kulkarni at morganstanley dot com>]

Ahh cool.. That worked!!

And there I was trying to do some fancy casting business (trying to
simulate the __cxa_call_unexpected(void *) function by looking at its
source code. )

Thanks a lot,
Mayuresh.


    | -----Original Message-----
    | From: Daniel Jacobowitz [mailto:drow@false.org] 
    | Sent: Sunday, October 29, 2006 5:22 PM
    | To: Kulkarni, Mayuresh (IT)
    | Cc: gdb@sourceware.org
    | Subject: Re: Finding the type of an exception
    | 
    | On Sun, Oct 29, 2006 at 05:15:47PM -0500, Kulkarni, 
    | Mayuresh (IT) wrote:
    | > Hello,
    | > 
    | > I am looking at a core generated by a C++ process 
    | because a throw spec 
    | > was violated by a function.
    | > 
    | > The concerned frame in the stack trace is :
    | > #5  0xf65c2485 in __cxa_call_unexpected 
    | (exc_obj_in=0xb58cbb4) at
    | > /sw/gcc/src/libstdc++-v3/libsupc++/eh_personality.cc:485
    | > 
    | > 
    | > At this point in the process (after std::unexpected() 
    | has been called 
    | > and we end up in the above function), is it still 
    | somehow possible to 
    | > deduce the type of the exception from the exc_obj_in 
    | void * argument?
    | > Say by trying to interpret the above void * argument as a 
    | > std::exception (from other reasons, I am pretty sure 
    | that this was a 
    | > std::exception) and then doing what typeid does to get 
    | at the type_info ?
    | 
    | The best place to look for more information about this is 
    | the common
    | C++ ABI document; it's named for Itanium, but don't let 
    | that throw you
    | off, it is actually used with only minor variations (such 
    | as the sizes of types) on other platforms.  You can learn 
    | more about it here:
    | 
    |   http://www.codesourcery.com/cxx-abi/abi.html
    |   http://www.codesourcery.com/cxx-abi/abi-eh.html
    | 
    | The object you've got there is a __cxa_exception, if I'm 
    | remembering how this works right.  If so then the first 
    | pointer is going to be to a type_info.
    | 
    | --
    | Daniel Jacobowitz
    | CodeSourcery
    |
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