minix/include/limits.h

/* The <limits.h> header defines some basic sizes, both of the language types 
 * (e.g., the number of bits in an integer), and of the operating system (e.g.
 * the number of characters in a file name.
 */

#ifndef _LIMITS_H
#define _LIMITS_H

/* Definitions about chars (8 bits in MINIX, and signed). */
#define CHAR_BIT           8	/* # bits in a char */
#define CHAR_MIN        -128	/* minimum value of a char */
#define CHAR_MAX         127	/* maximum value of a char */
#define SCHAR_MIN       -128	/* minimum value of a signed char */
#define SCHAR_MAX        127	/* maximum value of a signed char */
#define UCHAR_MAX        255	/* maximum value of an unsigned char */
#define MB_LEN_MAX         1	/* maximum length of a multibyte char */

/* Definitions about shorts (16 bits in MINIX). */
#define SHRT_MIN  (-32767-1)	/* minimum value of a short */
#define SHRT_MAX       32767	/* maximum value of a short */
#define USHRT_MAX     0xFFFF	/* maximum value of unsigned short */

/* _EM_WSIZE is a compiler-generated symbol giving the word size in bytes. */
#if _EM_WSIZE == 2
#define INT_MIN   (-32767-1)	/* minimum value of a 16-bit int */
#define INT_MAX        32767	/* maximum value of a 16-bit int */
#define UINT_MAX      0xFFFF	/* maximum value of an unsigned 16-bit int */
#endif

#if _EM_WSIZE == 4
#define INT_MIN (-2147483647-1)	/* minimum value of a 32-bit int */
#define INT_MAX   2147483647	/* maximum value of a 32-bit int */
#define UINT_MAX  0xFFFFFFFF	/* maximum value of an unsigned 32-bit int */
#endif

/*Definitions about longs (32 bits in MINIX). */
#define LONG_MIN (-2147483647L-1)/* minimum value of a long */
#define LONG_MAX  2147483647L	/* maximum value of a long */
#define ULONG_MAX 0xFFFFFFFFL	/* maximum value of an unsigned long */

#include <sys/dir.h>

/* Minimum sizes required by the POSIX P1003.1 standard (Table 2-3). */
#ifdef _POSIX_SOURCE		/* these are only visible for POSIX */
#define _POSIX_ARG_MAX    4096	/* exec() may have 4K worth of args */
#define _POSIX_CHILD_MAX     6	/* a process may have 6 children */
#define _POSIX_LINK_MAX      8	/* a file may have 8 links */
#define _POSIX_MAX_CANON   255	/* size of the canonical input queue */
#define _POSIX_MAX_INPUT   255	/* you can type 255 chars ahead */
#define _POSIX_NAME_MAX DIRSIZ	/* max. file name length */
#define _POSIX_NGROUPS_MAX   0	/* supplementary group IDs are optional */
#define _POSIX_OPEN_MAX     16	/* a process may have 16 files open */
#define _POSIX_PATH_MAX    255	/* a pathname may contain 255 chars */
#define _POSIX_PIPE_BUF    512	/* pipes writes of 512 bytes must be atomic */
#define _POSIX_STREAM_MAX    8	/* at least 8 FILEs can be open at once */
#define _POSIX_TZNAME_MAX    3	/* time zone names can be at least 3 chars */
#define _POSIX_SSIZE_MAX 32767	/* read() must support 32767 byte reads */
#define _POSIX_SYMLOOP_MAX   8	/* The number of symbolic links that can be
				 * traversed in the resolution of a pathname
				 * in the absence of a loop.
				 */

/* Values actually implemented by MINIX (Tables 2-4, 2-5, 2-6, and 2-7). */
/* Some of these old names had better be defined when not POSIX. */
#define _NO_LIMIT          100	/* arbitrary number; limit not enforced */

#define NGROUPS_MAX          0	/* supplemental group IDs not available */
#if _EM_WSIZE > 2
#define ARG_MAX          262144 /* # bytes of args + environ for exec() */
#else
#define ARG_MAX           4096	/* args + environ on small machines */
#endif
#define CHILD_MAX    _NO_LIMIT	/* MINIX does not limit children */
#define OPEN_MAX            30	/* # open files a process may have */
#if 0			/* V1 file system */
#define LINK_MAX      CHAR_MAX	/* # links a file may have */
#else			/* V2 or better file system */
#define LINK_MAX      SHRT_MAX	/* # links a file may have */
#endif
#define MAX_CANON          255	/* size of the canonical input queue */
#define MAX_INPUT          255	/* size of the type-ahead buffer */
#define NAME_MAX        DIRSIZ	/* # chars in a file name */
#define PATH_MAX           255	/* # chars in a path name */
#define PIPE_BUF          7168	/* # bytes in atomic write to a pipe */
#define STREAM_MAX          20	/* must be the same as FOPEN_MAX in stdio.h */
#define TZNAME_MAX           3	/* maximum bytes in a time zone name is 3 */
#define SSIZE_MAX        32767	/* max defined byte count for read() */
#define SYMLOOP_MAX	    16	/* maximum number of symbolic links that can
				 * be reliably traversed in the resolution of
				 * a pathname in the absence of a loop.
				 */

#endif /* _POSIX_SOURCE */

#endif /* _LIMITS_H */