Catch C++ exceptions on AIX with dbx

Question

I have a C++ application which terminates with a "bad allocation" error message for certain input data on an AIX machine.

Is there a way to run the program in dbx and catch the exception when it's being thrown? I don't see anything about it in IBM's documentation.

Answer 1

If your C++ application is compiled with XL C/C++, set a breakpoint on __DoThrowV6.

$ cat throw.C
int foo(int x)
{
   if (x < 0)
      throw 99;
   return x+1;
}

int main()
{
   int y;
   y = -5;
   try
   {
     foo(y);
   }
   catch(...)
   {
   }
   return 0;
}

$ xlC -g -o throw throw.C

$ dbx ./throw
Type 'help' for help.
reading symbolic information ...
(dbx) stop in __DoThrowV6
[1] stop in __DoThrowV6
(dbx) run
[1] stopped in __DoThrowV6 at 0xd1be7e00
0xd1be7e00 (__DoThrowV6)    7c0802a6        mflr   r0
(dbx) where
__DoThrowV6() at 0xd1be7e00
foo(int)(x = -5), line 4 in "throw.C"
main(), line 14 in "throw.C"
(dbx)

__DoThrowV6 is called when an exception is thrown, so from the call stack one can see that the exception was thrown from line 4 of the source file throw.C