Re: Name mangling

Young Wei Kuan wrote:


> I understand g++ 3.0 has changed its name-mangling scheme.
> [...] Why is it that object code compiled by g++ 2.95 is incompatible with
> that of gcc3.0?


Object code compiled by g++ 2.95 is incompatible with that of g++ 3.0
because of changes in the way things are implemented. For example,
g++ 3.0 uses a different implementation of exception handling than g++
2.95 did. This affected compatibility with code compiled with g++
2.95, i.e. the ABI (Application Binary Interface) changed.


When compilers change the way things are implemented in ways that
change the ABI, they often change the name-mangling scheme at the same
time, to prevent users from accidentally linking together components
that are not compatible and which might fail mysteriously at run-time
if they were linked together. Using a different name mangling scheme
can ensure that such problems result in link errors rather than
run-time crashes.


However, I don't know if that is what motivated changes in name
mangling between g++ 2.95 and g++ 3.0, or whether they were needed for
other reasons (e.g. standard-conformant handling of certain template
constructs).
--
Fergus Henderson <fjh@cs.mu.oz.au> | "I have always known that the pursuit
The University of Melbourne | of excellence is a lethal habit"
WWW: <http://www.cs.mu.oz.au/~fjh> | -- the last words of T. S. Garp.

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