c++ linker , how to link the iostream file?

Question

I have a file named main.cpp which includes iostream .

I compiled main.cpp and it worked without errors, so my question is: I compiled main.cpp and I did not link iostream with main.cpp , so how could this be possible? Or did the compiler linked the iostream automatically?

Answer 1

The functions in iostream are part of the C++ standard library, which you usually don't need to link explicitly.

If you use a compiler that's not strictly a C++ compiler, you sometimes need to add something like -lstdc++ (at least, I do if I use gcc rather than g++ ).

Answer 2

The iostream library is part of the “compiler”, in the largest sense of the word, and if you invoke the linker through the C++ compiler driver, ( g++ , cl , etc.), it will be automatically included; IDE's also generally arrange for it to be automatically included. If you invoke the linker directly ( ld , link , etc.), then you'll generally have to specify it explicitly. The same thing is true if the compiler driver doesn't understand C++ (the case of gcc ).