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Re: Unwinding stack past main() when it has another name
On Fri, Jun 17, 2005 at 08:22:13AM -1100, Steven Johnson wrote:
> Daniel Jacobowitz wrote:
>
> >The fact that we stop at _start is a feature, so hopefully you can rely
> >on that in the future.
> >
> >For some non-C languages we get the name of the main function from
> >debug information, but for C it's always main()
> >
> >
> This isnt always the case for embedded targets. There is no RULE that C
> programs must have a main() function. It may be that most do by
> convention, but they dont have to. In fact, main() can be a pain for
> small embedded targets because it wants a return value and arguments,
> which mean nothing for a program that isnt "launched" by a user on
> demand, but the C compiler detects the special function name main() and
> objects if it doesnt have the standard format. Programs dont even need
> to have an entry point called _start. It all depends on how you set up
> your link map.
In fact you're wrong: there is a rule that C programs must have a
main() function. It's in the language standard.
The fact that many embedded toolchains allow you to do things
differently is outside the boundaries of the language standard, and if
you don't have a main() your backtraces will stop at your entry point,
determined from the ELF file. GDB'll do the best it can.
--
Daniel Jacobowitz
CodeSourcery, LLC