xref: /aosp_15_r20/bionic/libc/include/limits.h (revision 8d67ca893c1523eb926b9080dbe4e2ffd2a27ba1)
1 /*
2  * Copyright (c) 1988 The Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  * 3. Neither the name of the University nor the names of its contributors
14  *    may be used to endorse or promote products derived from this software
15  *    without specific prior written permission.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27  * SUCH DAMAGE.
28  *
29  *	@(#)limits.h	5.9 (Berkeley) 4/3/91
30  */
31 
32 #pragma once
33 
34 /**
35  * @file limits.h
36  * @brief Constants relating to implementation limits.
37  *
38  * This file is included via `#include_next` from the clang header of the same
39  * name that provides all the limits that the compiler is responsible for,
40  * primarily those relating to integer types defined by the C standard.
41  * This file defines the additional limits defined by POSIX.
42  */
43 
44 /*
45  * The Android build system has bionic _before_ the clang headers,
46  * so although the claim above that clang does an `#include_next`
47  * of this file is true for the NDK, it's not true for the OS,
48  * and we need to paper over that difference here until/unless
49  * the OS build changes.
50  */
51 #if __has_include_next(<limits.h>)
52 #include_next <limits.h>
53 #endif
54 
55 #include <sys/cdefs.h>
56 
57 /* Historically bionic exposed the content of <float.h> from <limits.h> and <sys/limits.h> too. */
58 #include <float.h>
59 
60 /* Many of the POSIX limits come from the kernel. */
61 #include <linux/limits.h>
62 
63 /*
64  * bionic always exposed these alternative names,
65  * but clang's <limits.h> considers them GNU extensions,
66  * and may or may not have defined them.
67  */
68 #ifndef LONG_LONG_MIN
69 /** Non-portable synonym; use LLONG_MIN directly instead. */
70 #define LONG_LONG_MIN LLONG_MIN
71 #endif
72 #ifndef LONG_LONG_MAX
73 /** Non-portable synonym; use LLONG_MAX directly instead. */
74 #define LONG_LONG_MAX LLONG_MAX
75 #endif
76 #ifndef ULONG_LONG_MAX
77 /** Non-portable synonym; use ULLONG_MAX directly instead. */
78 #define ULONG_LONG_MAX ULLONG_MAX
79 #endif
80 
81 /** Maximum number of positional arguments in a printf()/scanf() format string. */
82 #define NL_ARGMAX 9
83 /** Maximum number of bytes in a $LANG name. */
84 #define NL_LANGMAX 14
85 /** Irrelevant with Android's <nl_types.h>. */
86 #define NL_MSGMAX 32767
87 /** Obsolete; removed from POSIX. */
88 #define NL_NMAX 1
89 /** Irrelevant with Android's <nl_types.h>. */
90 #define NL_SETMAX 255
91 /** Irrelevant with Android's <nl_types.h>. */
92 #define NL_TEXTMAX 255
93 
94 /** Obsolete; removed from POSIX. */
95 #define PASS_MAX 128
96 /** Obsolete; removed from POSIX. */
97 #define TMP_MAX 308915776
98 
99 /** Number of bits in a `long` (POSIX). */
100 #if __LP64__
101 #define LONG_BIT 64
102 #else
103 #define LONG_BIT 32
104 #endif
105 /** Number of bits in a "word" of `int` (POSIX). */
106 #define WORD_BIT 32
107 
108 /** Maximum value of a uid_t. */
109 #define UID_MAX UINT_MAX
110 /** Maximum value of a gid_t. */
111 #define GID_MAX UINT_MAX
112 /** Maximum value of a size_t. */
113 #define SIZE_T_MAX ULONG_MAX
114 /** Maximum value of a ssize_t. */
115 #define SSIZE_MAX LONG_MAX
116 
117 /** Maximum number of bytes in a multibyte character. */
118 #define MB_LEN_MAX 4
119 
120 /** Default process priority. */
121 #define NZERO 20
122 
123 /** Maximum number of struct iovec that can be passed in a single readv()/writev(). */
124 #define IOV_MAX 1024
125 
126 /** Maximum value for a semaphore. */
127 #define SEM_VALUE_MAX 0x3fffffff
128 
129 /** Do not use: prefer getline() or asprintf() rather than hard-coding an arbitrary size. */
130 #define LINE_MAX _POSIX2_LINE_MAX
131 
132 /* POSIX says these belong in <unistd.h> but BSD has some in <limits.h>. */
133 #include <bits/posix_limits.h>
134 
135 /** Maximum length of a hostname returned by gethostname(). */
136 #define HOST_NAME_MAX _POSIX_HOST_NAME_MAX
137 
138 /** Maximum length of a login name. */
139 #define LOGIN_NAME_MAX 256
140 
141 /** Maximum length of terminal device name. */
142 #define TTY_NAME_MAX 32
143 
144 /** Maximum number of attempts to destroy thread-specific data when a thread exits. */
145 #define PTHREAD_DESTRUCTOR_ITERATIONS _POSIX_THREAD_DESTRUCTOR_ITERATIONS
146 
147 /**
148  * The number of calls to pthread_key_create() without intervening calls to
149  * pthread_key_delete() that are guaranteed to succeed. See pthread_key_create()
150  * for more details and ways to avoid hitting this limit.
151  */
152 #define PTHREAD_KEYS_MAX 128
153 
154 /** bionic has no fixed limit on the number of threads. */
155 #undef PTHREAD_THREADS_MAX
156