Do I need an extern “C” block to include standard POSIX C headers?

Question

Do I need an extern \"C\" {} block to include standard C headers in a C++ program. Only consider standard C headers which do not have counterparts in C++.

Answer 1

Yes, you do. However, many systems (notably Linux) are already adding an extern "C" bracketing like you do. See (on Linux) files /usr/include/unistd.h /usr/include/features.h and the macro __BEGIN_DECLS defined in /usr/include/sys/cdefs.h and used in many Linux system include files.

So on Linux, you usually can avoid your extern "C" but it does not harm (and, IMHO, improve readability in that case).