Re: /Od compiler option problem
- From: "babak" <babak.ayani@xxxxxxxxx>
- Date: 18 Oct 2005 07:30:55 -0700
William DePalo [MVP VC++] skrev:
> "babak" <babak.ayani@xxxxxxxxx> wrote in message
> news:1129637454.399006.291190@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> > I am running a project in eVC 4.0 and I have been running into a bug
> > that only appears in the release build of the project. I eventually
> > found out that when I had the compiler option /Od set the project would
> > work properly but when it was not set the bug would appear.
> > I looked for /Od in the MSDN library but it didn't provide much help.
> > Can anyone help me with what in my code that could lead to this? I.e
> > what should I look for in my project to fix this bug?
>
> /Od means "disable the optimizing compiler". With optimizations disabled,
> the job of the compiler is simply (well, ok not simply <g>) to translate
> source code to object code. It is important to disable optimizations while
> debugging to keep the compiler from storing variables in registers, moving
> non-varying quantities outside of loops, reordering statements etc. If it
> did any of that it would be almost impossible to debug.
>
> When optimizations are enabled the compiler may do those things and more. In
> general, that's a good thing as it speeds up execution. The downside is that
> it may reveal latent bugs or introduce its own.
>
> > Is it ok to have this option set in a release build? What are the
> > consequences of that?
>
> Technically yes. Practically no. That's because you may not be pleased at
> the resulting execution speed with optimizations disabled.
>
> I would first try to replace Od by O1 and then O2. If either works I'd
> declare success and call it a day. If neither does you may want to try
> enabling optimizations on a file-by-file basis. If that works, then you
> enable optimizations one at a time until it breaks. At that point you can
> declare success again or you can try to find the cause.
>
> To do that add
>
> #pragma optimize("", off)
>
> at the top of a source file
>
> and
>
> #pragma optimize("", on)
>
> Then what you do is successfully shrink the size of the non-optimized region
> (moving off lower down the file, moving on higher up) until you find the
> stretch of code where optimization fails.
>
> Then post that _short_ stretch here and someone will likely be able to
> suggest a work-around.
>
> Regards,
> Will
William and Carl
Thanks a lot for your help. I will try your suggestions and get back if
the problem still exists.
Regards.
/Babak
.
- References:
- /Od compiler option problem
- From: babak
- Re: /Od compiler option problem
- From: William DePalo [MVP VC++]
- /Od compiler option problem
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