llvm-capstone/libcxx/include/climits
Louis Dionne 8cedff10a1 [libc++] Diagnose when header search paths are set up incorrectly
An issue I often see in codebases compiled for unusual platforms is
that header search paths are specified manually and are subtly wrong.
For example, people will manually add `-isystem <some-toolchain>/usr/include`,
which ends up messing up the layering of header search paths required by
libc++ (because the C Standard Library now appears *before* libc++ in
the search paths). Without this patch, this will end up causing
compilation errors that are pretty inscrutable. This patch aims to
improve the user experience by diagnosing this issue explicitly.

In all cases I can think of, I would expect that a compilation error
occur if these header search paths are not layered properly. This
should only provide an explicit diagnostic instead of failing due
to seemingly unrelated compilation errors.

Differential Revision: https://reviews.llvm.org/D131441
2022-08-17 14:05:26 -04:00

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1.4 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_CLIMITS
#define _LIBCPP_CLIMITS
/*
climits synopsis
Macros:
CHAR_BIT
SCHAR_MIN
SCHAR_MAX
UCHAR_MAX
CHAR_MIN
CHAR_MAX
MB_LEN_MAX
SHRT_MIN
SHRT_MAX
USHRT_MAX
INT_MIN
INT_MAX
UINT_MAX
LONG_MIN
LONG_MAX
ULONG_MAX
LLONG_MIN // C99
LLONG_MAX // C99
ULLONG_MAX // C99
*/
#include <__assert> // all public C++ headers provide the assertion handler
#include <__config>
#include <limits.h>
#ifndef _LIBCPP_LIMITS_H
# error <climits> tried including <limits.h> but didn't find libc++'s <limits.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 // _LIBCPP_CLIMITS