How to set breakpoints before mainCRTStartup?

[Steve Coleman]

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().

Hope this helps.

Steve.




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