cppdraft_translate/cppdraft/support/c/headers/general.md

[support.c.headers.general]

17 Language support library [support]

17.15 C headers [support.c.headers]

17.15.1 General [support.c.headers.general]

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For compatibility with theC standard library, the C++ standard library provides the C headers shown in Table 47.

The intended use of these headers is for interoperability only.

It is possible that C++ source files need to include one of these headers in order to be valid C. Source files that are not intended to also be valid C should not use any of the C headers.

[Note 1:

The C headers either have no effect, such as <stdbool.h> and <stdalign.h>, or otherwise the corresponding header of the form <cname> provides the same facilities and assuredly defines them in namespace std.

— end note]

[Example 1:

The following source file is both valid C++ and valid C. Viewed as C++, it declares a function with C language linkage; viewed as C it simply declares a function (and provides a prototype).

#include <uchar.h> // for char8_t in C, not necessary in C++#include <stddef.h> // for size_t#ifdef __cplusplus // see [cpp.predefined]extern "C" // see [dcl.link]#endifvoid f(char8_t s[], size_t n); — end example]

Table 47 — C headers [tab:c.headers]

🔗 <assert.h>	<inttypes.h>	<signal.h>	<stdckdint.h>	<tgmath.h>
🔗 <complex.h>	<iso646.h>	<stdalign.h>	<stddef.h>	<time.h>
🔗 <ctype.h>	<limits.h>	<stdarg.h>	<stdint.h>	<uchar.h>
🔗 <errno.h>	<locale.h>	<stdatomic.h>	<stdio.h>	<wchar.h>
🔗 <fenv.h>	<math.h>	<stdbit.h>	<stdlib.h>	<wctype.h>
🔗 <float.h>	<setjmp.h>	<stdbool.h>	<string.h>