How to set breakpoints before mainCRTStartup?

[Dalibor Topic]

Steve Coleman wrote:
> Dalibor Topic wrote:
> 
>> Dalibor Topic wrote:
>>
>>> Hi all,
>>>
>>> in my attempts to fix an ugly bug in kaffe on Cygwin, the bug I'm 
>>> trying to squish turned out to be triggered by something that happens 
>>> *before* main is called.
>>
>>
> <snip>
> 
>>> Since I'd like to know what modifes that opcode, I hope to be able to 
>>> set a breakpoint in gdb on the code that is executed before main in 
>>> Cygwin.
>>>
> Try running gdb with the "-command=<file name>" option and put a line in 
> it like "br myfunc". I have not tried this with cygwin gdb but it works 
> for me on several other OS's i use.
> 
>>> Any idea how to do that, i.e. where to put the breakpoint? Are there 
>>> some docs on what happends before main() on cygwin that I could look 
>>> up for reference while trying to hunt down this bug?
>>
>>
>>
>> It turns out that the bug happens even before mainCRTStartup.
>>
>> Has anyone seen something like that before?
> 
> 
> I have seen something like this before. If it is a C++ app then it may 
> be a constructor in a statically or golbally declared object instance. 
> The compiler should generate code to call all the global object 
> constructors for initializing these objects *before* calling main().

Thanks, but kaffe is written in C, so global constructors can't be a 
problem here. OTOH, maybe some part of Cygwin is written in C++ and may 
be responsible for the damage?

cheers,
dalibor topic


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