From: Andris <pavenis AT lanet DOT lv>
Organization: Pavenis
To: djgpp AT delorie DOT com, Gisle Vanem <giva AT bgnett DOT no>
Subject: Re: Detecting debugger
Date: Sat, 14 Sep 2002 17:19:01 +0300
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Reply-To: djgpp AT delorie DOT com

On Saturday 14 September 2002 18:53, Gisle Vanem wrote:
> Hi,
>
> I have a strange situation where running a program under a debugger
> (RHIDE or GDB) will hang the debugger on the call to a particular
> function. So I need to prevent calling this function when the program
> is a debugee. How do I detect running under a debugger?
>
> For the record, here is that function:
>
> static inline void Wait (void)   /* wait until timer changes */
> {
>   unsigned long t = _farpeekl (_dos_ds,0x46C);
>   while (_farpeekl(_dos_ds,0x46C) == t)
>         ((void)0);
> }
>

It's generally not a good idea to do such wait in so tight loop.
Such loop perhaps does not touch any memory using DS 
segment register (only a guess as I did not tried to compile and 
inspect generated assembler source), so it's not interruptable with Ctrl-Break 
or Ctrl-C. Therefore I would suggest to call __dpmi_yield() in loop and see 
whether problem remains instead of trying to detect when a programm is being 
run under debugger

Andris