Robert Shearman wrote:
Alex Villacís Lasso wrote:
Last weekend, I was trying to trace down bug #5245 (Run-Time error
'6' overflow in terragen). With current CVS, the bug manifests itself
with an "Overflow" dialog when starting up Terragen. However, this
bug does *not* go away with a native oleaut32.dll (taken from win98),
so this does not seem like an OLE bug. When running the program with
the debugger, the underlying exception trapped before displaying the
dialog reads "inexact float result", with a backtrace that comes out
of the bowels of msvbvm60.dll (weird - NOT inside Terragen.exe, and
NOT inside Terragen.dll). However, if the user types "pass" at the
debugger prompt, the dialog box does not appear, and the program
continues "normally". The exception occurs again whenever a File Open
dialog is dismissed, and again, typing "pass" lets the program run
normally.
Several questions:
- Can programs that execute floating-point instructions get the
"inexact float result" exception without any explicit setup, or do
they have to call some API in order to enable this notification? If
so, is it described in MSDN?
I believe it is an exception code raised by VB itself, not the result
of a floating point operation. I've seen it before and it usually
means that something unexpected happened under the covers in the VB
runtime. However, I would have expected it to be a bug inside
oleaut32, but that appears not to be the case here. Have you tried
running with native ole32 and rpcrt4 as well to see if the bug
disappears?
I will try that when I get home. I remember that I even tried
disassembling the code a few instructions before the addresses indicated
in the stack trace, and I saw a FIMUL 0x0(%esi) as the source of the
exception, in the code of msvbvm60.dll.
- Is the described behavior normal for the "pass" command? I was
expecting the command to make the app show the Overflow dialog and
then exit.
I don't think so. It should have the same behaviour as when running.
Is this, therefore, a bug in the debugger?
Alex Villacís Lasso
