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Date: Sat, 23 Feb 2002 12:56:00 -0000
From: Craig Rodrigues <rodrigc@attbi.com>
To: libstdc++@gcc.gnu.org
Cc: gcc@gcc.gnu.org
Subject: Throwing exception in constructor causes segfault
Message-ID: <20020223150023.A3639@attbi.com>
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Hi,

The following testcase was submitted in PR 5757:

class X
{
public:
  X ()
  {
    throw ""; 
  }

  ~X ()
  {
  }
};

int
main ()
{
  try
  {
    X *p = new X[4];
   delete[]p;
  }
  catch (...)
  {
  }
  return 0;
}


If this example is run, a segfault occurs.

The backtrace of the segfault is:
#0  operator delete[](void*) (ptr=0x804aa34) at del_opv.cc:36
#1  0x08048963 in main () at t.cpp:20
#2  0x401202ae in __libc_start_main (main=0x8048890 <main>, argc=1, 
    ubp_av=0xbffff754, init=0x8048670 <_init>, fini=0x8048a50 <_fini>, 
    rtld_fini=0x4000cf28 <_dl_fini>, stack_end=0xbffff74c)
    at ../sysdeps/generic/libc-start.c:129


I don't know how this stuff works, but I am guessing
that for some reason, during the stack unwinding, the
destructor is being called on *p, even though it
is not fully constructed, and this is causing problems.

Does anyone have any ideas about this?

Thanks.
-- 
Craig Rodrigues        
http://www.gis.net/~craigr    
rodrigc@attbi.com