[patch] fix spurious SIGSEGV faults under Cygwin

Dave Korn dave.korn@artimi.com
Thu Feb 2 17:47:00 GMT 2006

On 02 February 2006 17:42, Brian Dessent wrote:

> Dave Korn wrote:
>>   I'm having a conceptual difficulty here: Under what circumstances
>> would you expect there *not* to be a debugger attached to the inferior
>> to which the debugger is attached?  That's a bit zen, isn't it? 
> The code in question here runs many times in the normal course of any
> Cygwin program -- debugger or no.  The idea behind guarding the call to 
> OutputDebugString() with "if (being_debugged())" was that the call to
> IsDebuggerPresent() was cheaper than the call to OutputDebugString(), and
> that a well-behaived, non-debug build of a binary should not needlessly
> send tons and tons of nonsense to OutputDebugString unless it's actually
> being debugged and there is something there to interpret the nonsense.   

  Um, that's two people now who thought I was referring to the cygwin side of the patch.

  No, this is the bit of your post that I was replying to:

"then gdb could simply read that variable in the process' memory before deciding whether to handle the fault. "

  Is it the case that IsDebuggerPresent doesn't detect when gdb is attached?

Can't think of a witty .sigline today....

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