Tidy up and document <limits.h>. In particular, defer to clang for anything clang is willing to supply. Change-Id: I12cb6918fbfe453e07511c99fc0dd892910ea7c1
diff --git a/libc/include/limits.h b/libc/include/limits.h index e1f566c..132f1ed 100644 --- a/libc/include/limits.h +++ b/libc/include/limits.h
@@ -1,6 +1,3 @@ -/* $OpenBSD: limits.h,v 1.13 2005/12/31 19:29:38 millert Exp $ */ -/* $NetBSD: limits.h,v 1.7 1994/10/26 00:56:00 cgd Exp $ */ - /* * Copyright (c) 1988 The Regents of the University of California. * All rights reserved. @@ -32,108 +29,83 @@ * @(#)limits.h 5.9 (Berkeley) 4/3/91 */ -#ifndef _LIMITS_H_ -#define _LIMITS_H_ +#pragma once #include <sys/cdefs.h> +/* Defer to the compiler for the built-in C types. */ +#include_next <limits.h> + /* Historically bionic exposed the content of <float.h> from <limits.h> and <sys/limits.h> too. */ #include <float.h> +/* Many of the POSIX limits come from the kernel. */ #include <linux/limits.h> -#define PASS_MAX 128 /* _PASSWORD_LEN from <pwd.h> */ - -#define NL_ARGMAX 9 -#define NL_LANGMAX 14 -#define NL_MSGMAX 32767 -#define NL_NMAX 1 -#define NL_SETMAX 255 -#define NL_TEXTMAX 255 - -#define TMP_MAX 308915776 - -/* TODO: get all these from the compiler's <limits.h>? */ - -#define CHAR_BIT 8 -#ifdef __LP64__ -# define LONG_BIT 64 -#else -# define LONG_BIT 32 +/* + * bionic always exposed these alternative names, + * but clang's <limits.h> considers them GNU extensions, + * and may or may not have defined them. + */ +#ifndef LONG_LONG_MIN +/** Non-portable synonym; use LLONG_MIN directly instead. */ +#define LONG_LONG_MIN LLONG_MIN #endif +#ifndef LONG_LONG_MAX +/** Non-portable synonym; use LLONG_MAX directly instead. */ +#define LONG_LONG_MAX LLONG_MAX +#endif +#ifndef ULONG_LONG_MAX +/** Non-portable synonym; use ULLONG_MAX directly instead. */ +#define ULONG_LONG_MAX ULLONG_MAX +#endif + +/** Maximum number of positional arguments in a printf()/scanf() format string. */ +#define NL_ARGMAX 9 +/** Maximum number of bytes in a $LANG name. */ +#define NL_LANGMAX 14 +/** Irrelevant with Android's <nl_types.h>. */ +#define NL_MSGMAX 32767 +/** Obsolete; removed from POSIX. */ +#define NL_NMAX 1 +/** Irrelevant with Android's <nl_types.h>. */ +#define NL_SETMAX 255 +/** Irrelevant with Android's <nl_types.h>. */ +#define NL_TEXTMAX 255 + +/** Obsolete; removed from POSIX. */ +#define PASS_MAX 128 +/** Obsolete; removed from POSIX. */ +#define TMP_MAX 308915776 + +/** Number of bits in a `long` (POSIX). */ +#if __LP64__ +#define LONG_BIT 64 +#else +#define LONG_BIT 32 +#endif +/** Number of bits in a "word" of `int` (POSIX). */ #define WORD_BIT 32 -#define SCHAR_MAX 0x7f /* max value for a signed char */ -#define SCHAR_MIN (-0x7f-1) /* min value for a signed char */ - -#define UCHAR_MAX 0xffU /* max value for an unsigned char */ -#ifdef __CHAR_UNSIGNED__ -# define CHAR_MIN 0 /* min value for a char */ -# define CHAR_MAX 0xff /* max value for a char */ -#else -# define CHAR_MAX 0x7f -# define CHAR_MIN (-0x7f-1) -#endif - -#define USHRT_MAX 0xffffU /* max value for an unsigned short */ -#define SHRT_MAX 0x7fff /* max value for a short */ -#define SHRT_MIN (-0x7fff-1) /* min value for a short */ - -#define UINT_MAX 0xffffffffU /* max value for an unsigned int */ -#define INT_MAX 0x7fffffff /* max value for an int */ -#define INT_MIN (-0x7fffffff-1) /* min value for an int */ - -#ifdef __LP64__ -# define ULONG_MAX 0xffffffffffffffffUL /* max value for unsigned long */ -# define LONG_MAX 0x7fffffffffffffffL /* max value for a signed long */ -# define LONG_MIN (-0x7fffffffffffffffL-1) /* min value for a signed long */ -#else -# define ULONG_MAX 0xffffffffUL /* max value for an unsigned long */ -# define LONG_MAX 0x7fffffffL /* max value for a long */ -# define LONG_MIN (-0x7fffffffL-1)/* min value for a long */ -#endif - -# define ULLONG_MAX 0xffffffffffffffffULL /* max value for unsigned long long */ -# define LLONG_MAX 0x7fffffffffffffffLL /* max value for a signed long long */ -# define LLONG_MIN (-0x7fffffffffffffffLL-1) /* min value for a signed long long */ - -/* GLibc compatibility definitions. - Note that these are defined by GCC's <limits.h> - only when __GNU_LIBRARY__ is defined, i.e. when - targetting GLibc. */ -#ifndef LONG_LONG_MIN -#define LONG_LONG_MIN LLONG_MIN -#endif - -#ifndef LONG_LONG_MAX -#define LONG_LONG_MAX LLONG_MAX -#endif - -#ifndef ULONG_LONG_MAX -#define ULONG_LONG_MAX ULLONG_MAX -#endif - -#if defined(__USE_BSD) || defined(__BIONIC__) /* Historically bionic exposed these. */ -# define UID_MAX UINT_MAX /* max value for a uid_t */ -# define GID_MAX UINT_MAX /* max value for a gid_t */ -#if defined(__LP64__) +/** Maximum value of a uid_t. */ +#define UID_MAX UINT_MAX +/** Maximum value of a gid_t. */ +#define GID_MAX UINT_MAX +/** Maximum value of a size_t. */ #define SIZE_T_MAX ULONG_MAX -#else -#define SIZE_T_MAX UINT_MAX -#endif -#endif - -#if defined(__LP64__) +/** Maximum value of a ssize_t. */ #define SSIZE_MAX LONG_MAX -#else -#define SSIZE_MAX INT_MAX -#endif +/** Maximum number of bytes in a multibyte character. */ #define MB_LEN_MAX 4 +/** Default process priority. */ #define NZERO 20 +/** Maximum number of struct iovec that can be passed in a single readv()/writev(). */ #define IOV_MAX 1024 + +/** Maximum value for a semaphore. */ #define SEM_VALUE_MAX 0x3fffffff /** Do not use: prefer getline() or asprintf() rather than hard-coding an arbitrary size. */ @@ -142,12 +114,17 @@ /* POSIX says these belong in <unistd.h> but BSD has some in <limits.h>. */ #include <bits/posix_limits.h> +/** Maximum length of a hostname returned by gethostname(). */ #define HOST_NAME_MAX _POSIX_HOST_NAME_MAX + +/** Maximum length of a login name. */ #define LOGIN_NAME_MAX 256 + +/** Maximum length of terminal device name. */ #define TTY_NAME_MAX 32 -/* >= _POSIX_THREAD_DESTRUCTOR_ITERATIONS */ -#define PTHREAD_DESTRUCTOR_ITERATIONS 4 +/** Maximum number of attempts to destroy thread-specific data when a thread exits. */ +#define PTHREAD_DESTRUCTOR_ITERATIONS _POSIX_THREAD_DESTRUCTOR_ITERATIONS /** * The number of calls to pthread_key_create() without intervening calls to @@ -156,7 +133,5 @@ */ #define PTHREAD_KEYS_MAX 128 -/** bionic has no specific limit on the number of threads. */ +/** bionic has no fixed limit on the number of threads. */ #undef PTHREAD_THREADS_MAX - -#endif /* !_LIMITS_H_ */