C ++库的C部分是自动C99吗？

Question

Are all the functions in a conformant C++98/03/0x implementation completely C99 conformant?

I thought C++0x added some C99 ( language ) features, but never heard or read anything definitive about the C library functions.

Just to avoid any confusion, I'm talking about a C++ program using functions declared in the <c*> header set.

Thanks.

Answer 1

Most of the C99 standard library has been imported in C++0X but not all. From memory, in what wasn't imported there are

• <ctgmath> simply includes <ccomplex> and <cmath> ,
• <ccomplex> behaves as if it included <complex>
• <cmath> has quite a few adjustment (providing overload and template functions completing the C99 provided one)
• Some other headers ( <cstdbool> , <iso646.h> , ...) have adjustments to take differences between language into account ( bool is primitive in C++, a macro provided by <stdbool.h> in C for instance), but nothing of the scope of the math part.

The headers <xxx.h> whose <cxx> form doesn't behaves as the C99 version simply declares the content of <cxxx> in the global namespace, they aren't nearer of the C99 <xxx.h> content.

A related thing: C++0X provides some headers in both cxxx and xxx.h forms which aren't defined in C99 ( <cstdalign> and <cuchar> , the second one is defined in a C TR)

(I remembered that a bunch of mathematical functions from C99 had been put in TR1 but not kept in C++0X, I was mistaken, that bunch of mathematical functions weren't part of C99 in the first place).

Answer 2

No. C++03 is aligned with ANSI C89/ISO C90, not C99.

The upcoming C++0x standard is expected to be aligned to some degree with C99. See paragraph 17.6.1.2 in the current draft which lists ccomplex , cinttypes , cstdint etc. Note that, as AProgrammer mentions, some headers aren't exactly the same; further, that the header cuchar is aligned with the C Technical Report 19769 rather than C99.