Re: using 'g++ -shared' causes Segmentation fault <address@hidden> <address@hidden.california.localhost>

[Robert Heller]

At 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 :)

The '-shared' option is for *creating* a shared library only, NOT for
linking a *program* to one -- you *NEVER* use -shared when you are
creating a *program*.  You use the -L and -l options to link with
libraries, both shared and static actually, depending on which is
available and depending on the presence or absence of the -static
switch. The -static forces a static link and is NOT the 'obverse' of
-shared -- DON'T be confused by their adjacent placement in the man
pages.  With modern O/Ss, the default is to link to the shared library
(lib<mumble>.so), unless one is not available.  So to link with the
shared libraries, you don't need any *extra* switches to 'force'
linking with the shared libraries -- it will happen automagically by
default.  You just need to specify the library names.

If you are discovering that you are NOT linking to the shared libraries
you thought you were going to link with there is something else going
on, like maybe the shared libraries are not installed in the proper
place or not installed at all.  You might need to include a -L<path>
option before the -l<lib> option or something.  You don't add the
'-shared' option.

So what you want is (assuming you are wanting libSDL.so and libGL.so):

g++ -o otestSDLa testSDLa.o -lSDL -lGL

or maybe 

g++ -o otestSDLa testSDLa.o -L/usr/local/lib -lSDL -lGL

or something like that.


-- 
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