C++ - include unistd.h: why not cunistd?

Question

It\'s said that when including C header files in C++, the \".h\" suffix should be removed and then add \"c\" at the beginning. For example, #include

Answer 1

Your algorithm is correct for most (all?) standard C headers, but unistd.h is not part of standard C so standard C++ in turn doesn't include it with the other c... headers.

Answer 2

unistd.h is not part of standard C. Standard C++ lib doesn't include it with the other c headers.

Answer 3

Because unistd.h never was part of the C language. It is part of the Operating System.

Answer 4

<unistd.h> , stands for unix standard header ,the name says it all.