Re:using 'g++ -shared' causes Segmentation fault

[Vipin Dravid]

> I *need* to use shared libs (SDL & openGl libs) and I guess it's
> -shared switch which set that 'linking option'. Every time I use it
> (-shared) ANY program I'm trying to run gives 'Segmentation fault'...

you may need to use shared libs, but surely not _execute_ them. you
will get undefined behaviour  on most platforms if you try to execute
a shared library. AFAIK, for shared lib compiled with "-shared", the
linker defines a bogus entry point and hence execve() results in a
segmentation fault.

You'd have a problem, if you are getting segmentation fault for the
executable which link your shared libraries. Is that the case ?

On 21 Jun 2006 06:50:49 -0700, Mateusz Krzeszowiec
<Mateusz.Krzeszowiec@gmail.com> wrote:
> Paul Pluzhnikov wrote:
> > "facedancer" <Mateusz.Krzeszowiec@gmail.com> writes:
> >
> > > I'm trying to learn c++ for Linux and I've got a big problem.
> >
> > Actually, you don't have a problem ...
>
> Actually, I have a problem :)
>
> I *need* to use shared libs (SDL & openGl libs) and I guess it's
> -shared switch which set that 'linking option'. Every time I use it
> (-shared) ANY program I'm trying to run gives 'Segmentation fault'...
>
> Yours
> poor noob :)
>
> >
> > > When I
> > > try to link shared libraries to my program it always outputs
> > > 'Segmentation fault' when I try to run it.
> >
> > You are trying to *run* a library, but libraries aren't "runnable"
> > on any OS I know of [1].
> >
> > > Of course I was trying to
> > > write something a bit more complicated ;) but after looking for a bug I
> > > removed all code and realized that the bug is not caused my my mistake.
> >
> > Yes, it is. Your mistake is trying to run something that isn't
> > intended to run.
> >
> > > g++ -c -otestSDL.o testSDLa.cpp
> > > g++ -shared -otestSDLa testSDLa.o
> > > ./testSDLa
> > > output: Segmentation fault
> >
> > Don't do that ... Do this instead:
> >
> > > g++ -otestSDL.o testSDLa.cpp
> > g++ -o testSDLa testSDL.o        # looks like you missed a step
> > > ./testSDLa
> > > output: ok
> >
> > Cheers,
> >
> > [1] Actually, on Linux 2 special libraries are runnable:
> > ld-linux.so.2 and libc.so.6. This is achieved via special assembly
> > magic, which is too advanced for a beginner to understand :)
> > --
> > In order to understand recursion you must first understand recursion.
> > Remove /-nsp/ for email.
>
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--
Regards,
V i p i n

Life is what happens to you while you are busy making other plans.
- John Lenon


--
Regards,
V i p i n

Life is what happens to you while you are busy making other plans.
- John Lenon