John Fine wrote: > I have accidentally mixed binaries compiled by gcc3.2.3 with binaries > compiled by gcc3.4.6 in both directions across the main program / .so > boundary. I did that in both x86 and AMD64 architectures. In all cases > I have had crashes, usually in std::string. Right: libstdc++ wasn't stable. > I have mixed gcc3.4.6 with each of gcc4.1.2 and gcc4.3.2 in similar > combinations (but only in AMD64) and seen no similar problems. It is now. > So there seems to be a significant change in std::string (or something > it depends on) somewhere between gcc3.2.3 and gcc3.4.6, but no similar > change since. > > So I think you would need to switch to some newer version in order to > provide compatibility across a range of versions, and then I guess you > would lose compatibility back to 3.3.3 Right. > BTW, if any of the experts here have specific warnings (what won't work) > across the range 3.4.6 through 4.3.2, I'd appreciate them. The fact > that it has all worked for me so far doesn't prove it is safe. Well, we had to change the ABI several times as we were tracking the development of the standard, and even after the multi-vendor C++ ABI was finalized, we still made a couple of mistakes that required a fix that broke binary compatibility. That was, if I remember correctly, gcc 3.2.x. It's been pretty stable ever since. It's pretty easy to see when the ABI has changed because we bump the major release number in the soname. Andrew.
