1// Copyright 2017 The Abseil Authors.
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// https://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14//
15// -----------------------------------------------------------------------------
16// File: policy_checks.h
17// -----------------------------------------------------------------------------
18//
19// This header enforces a minimum set of policies at build time, such as the
20// supported compiler and library versions. Unsupported configurations are
21// reported with `#error`. This enforcement is best effort, so successfully
22// compiling this header does not guarantee a supported configuration.
23
24#ifndef ABSL_BASE_POLICY_CHECKS_H_
25#define ABSL_BASE_POLICY_CHECKS_H_
26
27// Included for the __GLIBC_PREREQ macro used below.
28#include <limits.h>
29
30// Included for the _STLPORT_VERSION macro used below.
31#if defined(__cplusplus)
32#include <cstddef>
33#endif
34
35// -----------------------------------------------------------------------------
36// Operating System Check
37// -----------------------------------------------------------------------------
38
39#if defined(__CYGWIN__)
40#error "Cygwin is not supported."
41#endif
42
43// -----------------------------------------------------------------------------
44// Compiler Check
45// -----------------------------------------------------------------------------
46
47// We support MSVC++ 14.0 update 2 and later.
48// This minimum will go up.
49#if defined(_MSC_FULL_VER) && _MSC_FULL_VER < 190023918 && !defined(__clang__)
50#error "This package requires Visual Studio 2015 Update 2 or higher."
51#endif
52
53// We support gcc 4.7 and later.
54// This minimum will go up.
55#if defined(__GNUC__) && !defined(__clang__)
56#if __GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 7)
57#error "This package requires gcc 4.7 or higher."
58#endif
59#endif
60
61// We support Apple Xcode clang 4.2.1 (version 421.11.65) and later.
62// This corresponds to Apple Xcode version 4.5.
63// This minimum will go up.
64#if defined(__apple_build_version__) && __apple_build_version__ < 4211165
65#error "This package requires __apple_build_version__ of 4211165 or higher."
66#endif
67
68// -----------------------------------------------------------------------------
69// C++ Version Check
70// -----------------------------------------------------------------------------
71
72// Enforce C++11 as the minimum. Note that Visual Studio has not
73// advanced __cplusplus despite being good enough for our purposes, so
74// so we exempt it from the check.
75#if defined(__cplusplus) && !defined(_MSC_VER)
76#if __cplusplus < 201103L
77#error "C++ versions less than C++11 are not supported."
78#endif
79#endif
80
81// -----------------------------------------------------------------------------
82// Standard Library Check
83// -----------------------------------------------------------------------------
84
85// We have chosen glibc 2.12 as the minimum as it was tagged for release
86// in May, 2010 and includes some functionality used in Google software
87// (for instance pthread_setname_np):
88// https://sourceware.org/ml/libc-alpha/2010-05/msg00000.html
89#if defined(__GLIBC__) && defined(__GLIBC_PREREQ)
90#if !__GLIBC_PREREQ(2, 12)
91#error "Minimum required version of glibc is 2.12."
92#endif
93#endif
94
95#if defined(_STLPORT_VERSION)
96#error "STLPort is not supported."
97#endif
98
99// -----------------------------------------------------------------------------
100// `char` Size Check
101// -----------------------------------------------------------------------------
102
103// Abseil currently assumes CHAR_BIT == 8. If you would like to use Abseil on a
104// platform where this is not the case, please provide us with the details about
105// your platform so we can consider relaxing this requirement.
106#if CHAR_BIT != 8
107#error "Abseil assumes CHAR_BIT == 8."
108#endif
109
110// -----------------------------------------------------------------------------
111// `int` Size Check
112// -----------------------------------------------------------------------------
113
114// Abseil currently assumes that an int is 4 bytes. If you would like to use
115// Abseil on a platform where this is not the case, please provide us with the
116// details about your platform so we can consider relaxing this requirement.
117#if INT_MAX < 2147483647
118#error "Abseil assumes that int is at least 4 bytes. "
119#endif
120
121#endif // ABSL_BASE_POLICY_CHECKS_H_
122