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

55 lines
1.6 KiB
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
//
//===----------------------------------------------------------------------===//
// <string>
// ... manipulating sequences of any non-array trivial standard-layout types.
// XFAIL: FROZEN-CXX03-HEADERS-FIXME
#include <string>
#include "test_traits.h"
struct NotTrivial {
NotTrivial() : value(3) {}
int value;
};
struct NotStandardLayout {
public:
NotStandardLayout() : one(1), two(2) {}
int sum() const { return one + two; } // silences "unused field 'two' warning"
int one;
private:
int two;
};
void f() {
{
// array
typedef char C[3];
static_assert(std::is_array<C>::value, "");
std::basic_string<C, test_traits<C> > s;
// expected-error-re@string:* {{static assertion failed{{.*}}Character type of basic_string must not be an array}}
}
{
// not trivial
static_assert(!std::is_trivial<NotTrivial>::value, "");
std::basic_string<NotTrivial, test_traits<NotTrivial> > s;
// expected-error-re@string:* {{static assertion failed{{.*}}Character type of basic_string must be trivial}}
}
{
// not standard layout
static_assert(!std::is_standard_layout<NotStandardLayout>::value, "");
std::basic_string<NotStandardLayout, test_traits<NotStandardLayout> > s;
// expected-error-re@string:* {{static assertion failed{{.*}}Character type of basic_string must be standard-layout}}
}
}