limits(5) File Formats Manual limits(5)
Name
limits - header files for implementation-specific constants
Syntax
#include <limits.h>
#include <float.h>
Description
The header file <limits.h> specifies the sizes of integral types as required by the proposed ANSI C standard. The header file <float.h>
specifies the characteristics of floating types as required by the proposed ANSI C standard. The constants that refer to long doubles that
should appear in <float.h> are not specified because RISC does not implement long doubles.
The file <limits.h> contains the following:
#define CHAR_BIT 8 /* # of bits in a `char' */
#define SCHAR_MIN (-128) /* min integer value of a `signed */
/* char' */
#define SCHAR_MAX (+127) /* max integer value of a `signed */
/* char' */
#define UCHAR_MAX 255 /* max integer value of `unsigned */
/* char' */
#define CHAR_MIN (-128) /* min integer value of a `char' */
#define CHAR_MAX (+127) /* max integer value of a `char' */
#define SHRT_MIN (-32768) /* min decimal value of a `short' */
#define SHRT_MAX (+32767) /* max decimal value of a `short' */
#define USHRT_MAX 65535 /* max decimal value of `unsigned */
/* short' */
#define INT_MIN (-2147483648) /* min decimal value of an `int' */
#define INT_MAX (+2147483647) /* max decimal value of a `int' */
#define UINT_MAX 4294967295 /* max decimal value of `unsigned */
/* int' */
#define LONG_MIN (-2147483648) /* min decimal value of a `long' */
#define LONG_MAX (+2147483647) /* max decimal value of a `long' */
#define ULONG_MAX 4294967295 /* max decimal value of `unsigned */
/* long' */
#define USI_MAX 4294967295 /* max decimal value of `unsigned' */
#define WORD_BIT 32 /* # of bits in a ``word'' or */
/* `int' */
#define CHILD_MAX 25 /* max # of processes per user id */
#define CLK_TCK 60 /* # of clock ticks per second */
#define LOCK_MAX 0 */ max # of entries in system */
/* lock table */
#define LINK_MAX 32766 /* max # of links to a single */
/* file */
#define LONG_BIT 32 /* # of bits in a "long" (X/OPEN) */
#define NAME_MAX 255 /* max # of characters in a file name */
#define NGROUPS_MAX 32 /* max # of groups */
#define MAX_INPUT 256 /* max # of bytes in terminal */
/* input queue */
#define MAX_CANON 256 /* max # of bytes in term canon */
/* input line */
#define MAX_CHAR 256 /* max # of bytes in term canon */
/* input line (X/OPEN) */
#define OPEN_MAX 64 /* max # of files a process can */
/* have open */
#define PASS_MAX 8 /* max # of characters in */
/* a password */
#define PATH_MAX 1024 /* max # of characters in */
/* a path name */
#define PID_MAX 30000 /* max value for a process ID */
#define SYSPID_MAX 2 /* max value for a system */
/* proc ID (X/OPEN) */
#define PIPE_BUF 4096 /* max # bytes atomic in */
/* write to pipe */
#define PIPE_MAX 4096 /* max # bytes written to a */
/* pipe in a write */
#define PROC_MAX 100 /* max # of simultaneous processes */
#define STD_BLK 8192 /* # bytes in a physical I/O block */
#define SYS_NMLN 32 /* # of chars in uname-returned strings */
#define SYS_OPEN 200 /* max # of files open on system */
#define TMP_MAX 17576 /* max # of calls to tmpnam(3S) before */
/* recycling of names occurs */
#define UID_MAX 32000 /* max value for a user or group */
/* ID */
#define NZERO 20
/* default nice value (as seen */
/* by nice(3), not intrinsically) */
/*
* Internationalization constants
*/
#define MB_LEN_MAX 1 /* max number of bytes in a multibyte */
/* character, any locale: placeholder */
#define NL_ARGMAX 9 /* max value of digits in calls to */
/* nl_scanf(3S) and nl_printf(3S) */
#define NL_MSGMAX 32767 /* max message number */
#define NL_NMAX 2 /* max n-to-1 bytes in mapping chars */
#define NL_SETMAX 255 /* max set number */
#define NL_TEXTMAX 256 /* max no. of bytes in a message */
/* string */
#define NL_LBLMAX 32767 /* max number of labels */
/* in catalogue */
#define NL_LANGMAX 32 /* max number of bytes in LANG */
/* name */
/*
* POSIX minimum values
*
* These values are the MINIMUM allowable by POSIX. Actual values
* for ULTRIX are defined above.
*/
#define _POSIX_ARG_MAX 4096 /* Length of arguments for */
/* exec( ) */
#define _POSIX_CHILD_MAX 6 /* Number of simultaneous */
/* procs per uid */
#define _POSIX_LINK_MAX 8 /* Number of file links */
#define _POSIX_MAX_CANON 255 /* Number of bytes in */
/* a terminal canon */
/* input queue */
#define _POSIX_MAX_INPUT 255 /* Number of bytes */
/* for which space is */
/* guaranteed in terminal */
/* input queue */
#define _POSIX_NAME_MAX 14 /* Number of bytes in a filename */
#define _POSIX_NGROUPS_MAX 0 /* Number of allowable */
/* supplementary group ID's */
#define _POSIX_OPEN_MAX 16 /* Number of files open at one */
/* time by a given process. */
#define _POSIX_PATH_MAX 255 /* Number of bytes in a pathname */
#define _POSIX_PIPE_BUF 512 /* Number of bytes that is */
/* guaranteed to be written */
/* atomically when writing to */
/* a pipe. */
The file <limits.h> contains the following values for RISC architecture:
#define ARG_MAX 20480 /* max length of arguments to exec */
#define HUGE_VAL 1.8e+308 /* infinity */
The file <limits.h> contains the following value for VAX architecture:
#define ARG_MAX 10240 /* max length of arguments to exec */
The file <limits.h> contains the following value for VAX D-float architecture:
#define HUGE_VAL 1.701411834604692293e+38
The file <limits.h> contains the following value for VAX G-float architecture:
#define HUGE_VAL 8.9884656743115790e+307
The file <float.h> contains the following values for RISC architecture:
#define FLT_RADIX 2 /* radix of exponent representation */
#define FLT_ROUNDS 1 /* addition rounds */
/* (>0 implementation-defined) */
/* number of base-FLT_RADIX digits in the floating point mantissa */
#define FLT_MANT_DIG 24
#define DBL_MANT_DIG 53
/* minimum positive floating-point number x such that */
/* 1.0 + x < > 1.0 */
#define FLT_EPSILON 1.19209290e-07
#define DBL_EPSILON 2.2204460492503131e-16
/* number of decimal digits of precision */
#define FLT_DIG 6
#define DBL_DIG 15
/* minimum negative integer such that FLT_RADIX raised to that */
/* power minus 1 is a normalized floating point number */
#define FLT_MIN_EXP (-125)
#define DBL_MIN_EXP (-1021)
/* minimum normalized positive floating-point number */
#define FLT_MIN 1.17549435e-38
#define DBL_MIN 2.2250738585072014e-308
/* minimum negative integer such that 10 raised to */
/* that power is in the range of normalized floating-point numbers */
#define FLT_MIN_10_EXP (-37)
#define DBL_MIN_10_EXP (-307)
/* maximum integer such that FLT_RADIX raised to that */
/* power minus 1 is a representable finite floating-point number */
#define FLT_MAX_EXP +128
#define DBL_MAX_EXP +1024
/* maximum representable finite floating-point number */
#define FLT_MAX 3.40282347e+38
#define DBL_MAX 1.7976931348623157e+308
/* maximum integer such that 10 raised to that power is in */
/* the range of representable finite floating-point numbers */
#define FLT_MAX_10_EXP 38
#define DBL_MAX_10_EXP 308
The file <float.h> contains the following values for VAX architecture:
#define FLT_RADIX 2 /* radix of exponent representation */
#define FLT_ROUNDS 1 /* addition rounds */
/* (>0 implementation-defined) */
#define FLT_MIN_10_EXP (-37)
#define DBL_MIN_10_EXP (-307)
#define LDBL_MIN_10_EXP
#define FLT_MANT_DIG 24
#define FLT_EPSILON 5.96046448e-08
#define FLT_DIG 6
#define FLT_MIN_EXP (-127)
#define FLT_MIN float 2.93873588e-39
#define FLT_MIN_10_EXP (-38)
#define FLT_MAX_EXP 127
#define FLT_MAX 1.701411733192644299e+38
#define FLT_MAX_10_EXP 380
The file <float.h> contains the following values for VAX D-float:
#define DBL_MANT_DIG 56
#define DBL_EPSILON 1.3877787807814457e-17
#define DBL_DIG 16
#define DBL_MIN_EXP (-127)
#define DBL_MIN 2.93873587705571880e-39
#define DBL_MIN_10_EXP (-38)
#define DBL_MAX_EXP 127
#define DBL_MAX 1.701411834604692293e+38
#define DBL_MAX_10_EXP 38
The file <float.h> contains the following values for VAX G-float (cc - Mg):
#define DBL_MANT_DIG 53
#define DBL_EPSILON 1.1102230246251570e-016
#define DBL_DIG 15
#define DBL_MIN_EXP (-1023)
#define DBL_MIN 5.56268464626800350e-309
#define DBL_MIN_10_EXP (-308)
#define DBL_MAX_EXP 1023
#define DBL_MAX 8.9884656743115790e+307
#define DBL_MAX_10_EXP 307
RISC limits(5)