Difference between C standard library and C POSIX library

Question

I\'m a little confused by \"C standard lib\" and \"C POSIX lib\", because I found that, many header files defined in \"C POSIX lib\" are also part of \"C standard lib\".

Answer 1

ANSI C is still alive, I think: ANSI C is inherited and extended by ISO C, Cxx. POSIX have been obeying ANSI C absolutely."

We can write ANSI C on Windows, Unix-Like, embedded device easily; but Cxx, or POSIX may have issue.