LIMITS(F) UNIX System V
Name
limits - file header for implementation-specific constants
Syntax
#include <limits.h>
Description
The header file <limits.h> is a list of magnitude
limitations imposed by a specific implementation of the
operating system. All values are specified in decimal.
#define ARG_MAX 5120 /* max length of arguments to exec */
#define CHAR_BIT 8 /* # of bits in a "char" */
#define CHAR_MAX 127 /* max integer value of a "char" */
#define CHAR_MIN -128 /* min integer value of a "char" */
#define CHILD_MAX 25 /* max # of processes per user id */
#define CLK_TCK 100 /* # of clock ticks per second */
#define DBL_DIG 16 /* digits of precision of a "double" */
#define DBL_MAX 1.79769313486231470e+308 /*max decimal value of a "double"*/
#define DBL_MIN 4.94065645841246544e-324 /*min decimal value of a "double"*/
#define FCHR_MAX 1048576 /* max size of a file in bytes */
#define FLT_DIG 7 /* digits of precision of a "float" */
#define FLT_MAX 3.40282346638528860e+38 /*max decimal value of a "float" */
#define FLT_MIN 1.40129846432481707e-45 /*min decimal value of a "float" */
#define HUGE_VAL 3.40282346638528860e+38 /*error value returned by Math lib*/
#define INT_MAX 2147483647 /* max decimal value of an "int" */
#define INT_MIN -2147483648 /* min decimal value of an "int" */
#define LINK_MAX 1000 /* max # of links to a single file */
#define LONG_MAX 2147483647 /* max decimal value of a "long" */
#define LONG_MIN -2147483648 /* min decimal value of a "long" */
#define Name_MAX 14 /* max # of characters in a file name */
#define OPEN_MAX 60 /* max # of files a process can have open */
#define PASS_MAX 8 /* max # of characters in a password */
#define PATH_MAX 256 /* max # of characters in a path name */
#define PID_MAX 30000 /* max value for a process ID */
#define PIPE_BUF 5120 /* max # bytes atomic in write to a pipe */
#define PIPE_MAX 5120 /* max # bytes written to a pipe in a write */
#define SHRT_MAX 32767 /* max decimal value of a "short" */
#define SHRT_MIN -32768 /* min decimal value of a "short" */
#define STD_BLK 1024 /* # bytes in a physical I/O block */
#define SYS_NMLN 9 /* # of chars in uname-returned strings */
#define UID_MAX 60000 /* max value for a user or group ID */
#define USI_MAX 4294967295 /* max decimal value of an "unsigned" */
#define WORD_BIT 32 /* # of bits in a "word" or "int" */
Standards Conformance
limits is conformant with:
The X/Open Portability Guide II of January 1987.
(printed 2/15/90) LIMITS(F)