Re: [GnomeMeeting-list] Finally! Working gnomemeeting and Gatekeeper!

[Craig Southeren <craigs postincrement com>]

> De: "Chris Rankin" <rankincj yahoo com>
> Sujet: [GnomeMeeting-list] Finally! Working gnomemeeting and Gatekeeper!
> 
..deleted

> Someone has added the following compiler options to
> g++ when compiling Pwlib, and everything derived from
> it (including gnomemeeting):
> 
> -fno-rtti -ffunction-sections -fdata-sections
> 
> Removing RTTI is a *bad idea*, because it means that
> operations like "dynamic_cast<>" cannot work!

That someone was "me". Yes, this flag will prevent any code that
contains dynamic casts from being linked, which is not a problem as none
of the code for GM, PWlib or OpenH323 contains dynamic casts. It also
reduces the size of executable by about 5%, so there are benefits.

If anyone is using dynamic casts (rather than the portable PWLib
constructs that acheive the same result) then you are correct in that
they will need to remove this flag.

> (Catching exceptions might be affected too.) 

No, it is not. See the gcc manual for more information.

> Quite
> possibly gnomemeeting doesn't use dynamic_cast<>
> directly, but the pwlib/src/ptlib/unix/beaudio.cxx
> file does and so does the GNU Gatekeeper. 

The GNU gatekeeper will never be linked with GM, so this is not relevant.
The BeOS audio driver needs to be rewritten to use the new plugin audio
driver system so this is irelevant as well.

>The absence
> of any RTTI is why my new Gatekeeper immediately
> core-dumped whenever I tried to start it.

See above

> I'm not sure about the value of the other two compiler
> optimisations. The GCC manual has the following to say
> about them:

..deleted

Even though the intermediate object files and libraries are larger (due
to the additional linker information) the final executables are smaller
(as the linker can make better decisions about what to throw away). 

   Craig


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