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Re: How to set breakpoints before mainCRTStartup?


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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