> Ok, I got my compiler up and running and compiling some of my old works in C, > but now when I use even 'iostream' compiler finds eggog like that: > 'In file included from /usr/include/g++-v3/backward/stream.h:32, > from String.cc:14: > /usr/include/g++-v3/backward/iostream.h:35: using directive `ostream' > introduced ambiguous type `ostream'' > I know it's probably due to libraries versions mismatch, but I got libstdc++ > exactly the same version as gcc.
You will need to provide more details. Please run the compilation pass first with the "-v" option, to find out how the various passes of the compiler are invoked, then with the "--trace-includes" option, to find out what files are included in what order. My suspicion is that you managed to mix header files of different gcc versions, thus combining a 2.95 ::ostream definition with the 3.0 std::ostream. If you have two ostream classes (one on top-level, one in std), and you bring the second class on top-level with the using declaration, you get that error. That actually suggests a different cause: Compiling class ostream; #include <iostream.h> with gcc 3 will produce this exact error. The error is reported correctly by GCC: You must not forward-declare ostream. First, it is not a class (but a typedef for a template instantiation), and then, it is defined in std::, not in the global namespace. Earlier gcc versions (incorrectly) accepted that code, since they (incorrectly) defined ostream to be a global class themselves. Use <iosfwd> if you need forward declarations of ostream. In this case, nothing would be wrong with your compiler installation: the bug is in the source code. Regards, Martin
