Museum

 limits(FP)                     6 January 1993                     limits(FP)


 Name

    limits - header file 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 speci-
    fied 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    1.7976931348623157e+308 /* "double" max decimal value */
    #define DBL_MIN    2.2250738585072014e-308 /* "double" min decimal value */
    #define FCHR_MAX   1048576                 /* max size of a file in bytes */
    #define FLT_DIG    7                       /* digits of precision of a "float" */
    #define FLT_MAX    ((float)3.40282347e+38  /* "float" max decimal value */
    #define FLT_MIN    ((float)1.17549435e-38  /* "float" min decimal value */
    #define HUGE_VAL   3.40282346638528860e+38 /* error val. returned by libm */
    #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 filename */
    #define OPEN_MAX   60                      /* max # of open files for a process */
    #define PASS_MAX   8                       /* max # of characters in a password */
    #define PATH_MAX   256                     /* max # of characters in a pathname */
    #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 */
    #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:
    X/Open Portability Guide, Issue 3, 1989.