> I have found an apparent bug in gcc 3.4.4 under Cygwin. The attached test > case (and the code > it's derived from) works as expected with Cygwin gcc 3.3.3 with the exact > same Cygwin install > except the compiler packages. It also works fine with various versions of gcc > on other > platforms, including 3.4.2 (FC3) and 4.0 (FC4).
Here is the reason: When linking against the dll, you are notified: Info: resolving typeinfo for base_t by linking to __imp___ZTI6base_t (auto-import) typeinfo tables are readonly and so place in .rdata section. Auto-import doesn't work for .rdata because it depends on the linker writing a thunk to dereference the *__imp__foo. It gets away with this trickery for non-constant data by "casting" the .text section writeable. But the loader really does expect the contents of .rdata section to be non-writeable. If you lie to it, bad things happen. If we put readonly data in text section (as we did in gcc-3.3.x) then your testcase should work. It will also work if you don't use auto-import and explicitly mark the dllimport'd base_t class with __attribute__ ((dllimport)). Danny Send instant messages to your online friends http://au.messenger.yahoo.com
