In overload resolution, type conversion operators are now properly treated as always coming from the most derived class. Unfortunately, this only works on Linux if you're linking statically. Lots of bugs stomped. Namespaces are fully supported. The library has not yet been converted to use namespace std, however, and the old std-faking code is still on by default.
Exception handling is now thread safe, and supports nested exceptions and placement delete.
Exception handling overhead on x86 is much lower with GNU as 2.9. This ABI is subject to change without notice, so don't use it for anything that you don't want to rebuild with every release of the compiler. These pages are maintained by The GCC team . Verbatim copying and distribution of this entire article is permitted in any medium, provided this notice is preserved.