On Thu, 2004-07-15 at 15:14, Ludovic CourtÃs wrote: > Today, 12 minutes, 50 seconds ago, Ralf Corsepius wrote: > > This way you compile your whole program using the C++ compiler, i.e. you > > actually are compiling it as a C++ program, not as a c-program. > > Right. But it doesn't hurt much (wrt. mangled symbol names, for > instance) so long as you are compiling a program, not a library. You are treating your code as c++, not as c-code. > [...] > > > This only works with some (old) versions of gcc for some selected > > targets (eg. gcc-2.9x on i386). In general (esp. with gcc >= 3.0), it > > does not work. > > G++ 3.0.2 on i386 has `libstdc++' too. From my understanding of > http://gcc.gnu.org/onlinedocs/libstdc++/faq/index.html (especially 5.2), > `libstdc++' won't disappear from G++. Were you talking about `libg++'? No, I am referring to libstdc++. libstdc++ is an internal implementation detail of g++ you should not have to care about. However "presence of libstdc++" is not the actual problem, here. The actual problem is "using g++ to link" means more than adding "-lstdc++" to LDFLAGS. For example, on some targets w/ some gcc-versions it means adding further libs (e.g. libsupc++), composing ctors/dtors, pulling in alternative startup code etc. What it actually does highly depends on the gcc-version you are using and the target (architecture, OS, object format etc.) you are compiling for. > > > but other C++ > > > environments do not necessarily have `libstdc++'). In order to link > > > against a C++ library without having a C++ compiler, one needs to have > > > `libstdc++' (or equivalent) statically linked into the C++ library. > > Sorry, this is not true. > > > > With g++, in general, you have to use "g++" to link and must not > > explicitly add "-lstdc++". Admitted, there exist some occasions for some > > apps/libs on some architectures for some versions of gcc where the trick > > you describe sometimes work, but in general, this does not work. > > Yes, that's what I meant. However, one has to consider that the user > linking against your library doesn't necessarily have a C++ compiler and > runtime environment (think of a library implemented in C++ which > provides a plain C API). How would you accommodate such a situation if > not by linking the C++ lib against libstdc++.a or equivalent? This would be very hard. You'd have to design your library in such a way that it does not have any unresolved C++ symbol. In practice, this would mean to avoid using the STL and to avoid most features that make C++ attractive (no static constructors, no iostreams etc.). Furthermore, you'd have to set up your CXX-flags in such a way that it does not generate C++ symbols (type-info, exceptions). Ralf _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx http://lists.gnu.org/mailman/listinfo/autoconf
