C++ - include unistd.h: why not cunistd?
Solution 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.
Solution 2:
Because unistd.h never was part of the C language. It is part of the Operating System.
Solution 3:
<unistd.h> , stands for unix standard header ,the name says it all.
Solution 4:
unistd.h is not part of standard C. Standard C++ lib doesn't include it with the other c headers.