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

93 lines
2.0 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_CFLOAT
#define _LIBCPP_CFLOAT
/*
cfloat synopsis
Macros:
FLT_ROUNDS
FLT_EVAL_METHOD // C99
FLT_RADIX
FLT_HAS_SUBNORM // C11
DBL_HAS_SUBNORM // C11
LDBL_HAS_SUBNORM // C11
FLT_MANT_DIG
DBL_MANT_DIG
LDBL_MANT_DIG
DECIMAL_DIG // C99
FLT_DECIMAL_DIG // C11
DBL_DECIMAL_DIG // C11
LDBL_DECIMAL_DIG // C11
FLT_DIG
DBL_DIG
LDBL_DIG
FLT_MIN_EXP
DBL_MIN_EXP
LDBL_MIN_EXP
FLT_MIN_10_EXP
DBL_MIN_10_EXP
LDBL_MIN_10_EXP
FLT_MAX_EXP
DBL_MAX_EXP
LDBL_MAX_EXP
FLT_MAX_10_EXP
DBL_MAX_10_EXP
LDBL_MAX_10_EXP
FLT_MAX
DBL_MAX
LDBL_MAX
FLT_EPSILON
DBL_EPSILON
LDBL_EPSILON
FLT_MIN
DBL_MIN
LDBL_MIN
FLT_TRUE_MIN // C11
DBL_TRUE_MIN // C11
LDBL_TRUE_MIN // C11
*/
#if __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
# include <__cxx03/cfloat>
#else
# include <__config>
# include <float.h>
# ifndef _LIBCPP_FLOAT_H
# error <cfloat> tried including <float.h> but didn't find libc++'s <float.h> header. \
This usually means that your header search paths are not configured properly. \
The header search paths should contain the C++ Standard Library headers before \
any C Standard Library, and you are probably using compiler flags that make that \
not be the case.
# endif
# if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
# endif
#endif // __cplusplus < 201103L && defined(_LIBCPP_USE_FROZEN_CXX03_HEADERS)
#endif // _LIBCPP_CFLOAT