Nikolas Klauser b9a2658a3e
[libc++][C++03] Use __cxx03/ headers in C++03 mode (#109002)
This patch implements the forwarding to frozen C++03 headers as
discussed in
https://discourse.llvm.org/t/rfc-freezing-c-03-headers-in-libc. In the
RFC, we initially proposed selecting the right headers from the Clang
driver, however consensus seemed to steer towards handling this in the
library itself. This patch implements that direction.

At a high level, the changes basically amount to making each public
header look like this:

```
// inside <vector>
#ifdef _LIBCPP_CXX03_LANG
#  include <__cxx03/vector>
#else
  // normal <vector> content
#endif
```

In most cases, public headers are simple umbrella headers so there isn't
much code in the #else branch. In other cases, the #else branch contains
the actual implementation of the header.
2024-12-21 13:01:48 +01:00

66 lines
1.5 KiB
C++

// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_CTYPE_H
#define _LIBCPP_CTYPE_H
/*
ctype.h synopsis
int isalnum(int c);
int isalpha(int c);
int isblank(int c); // C99
int iscntrl(int c);
int isdigit(int c);
int isgraph(int c);
int islower(int c);
int isprint(int c);
int ispunct(int c);
int isspace(int c);
int isupper(int c);
int isxdigit(int c);
int tolower(int c);
int toupper(int c);
*/
#if defined(__cplusplus) && __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
# include <__cxx03/ctype.h>
#else
# include <__config>
# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
# endif
# if __has_include_next(<ctype.h>)
# include_next <ctype.h>
# endif
# ifdef __cplusplus
# undef isalnum
# undef isalpha
# undef isblank
# undef iscntrl
# undef isdigit
# undef isgraph
# undef islower
# undef isprint
# undef ispunct
# undef isspace
# undef isupper
# undef isxdigit
# undef tolower
# undef toupper
# endif
#endif // defined(__cplusplus) && __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
#endif // _LIBCPP_CTYPE_H