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Manual page for limits(4)

limits - header for implementation-specific constants

SYNOPSIS

#include <limits.h>

DESCRIPTION

The header <limits.h> is a list of minimal magnitude limitations imposed by a specific implementation of the operating system.

ARG_MAX      1048320                  /* max length of arguments to exec */
CHAR_BIT     8                        /* max # of bits in a "char" */
CHAR_MAX     255                      /* max value of a "char" */
CHAR_MIN     0                        /* min value of a "char" */
CHILD_MAX    25                       /* max # of processes per user id */
CLK_TCK      _sysconf(3)              /* clock ticks per second */
DBL_DIG      15                       /* digits of precision of a "double" */
DBL_MAX      1.7976931348623157E+308  /* max decimal value of a "double"*/
DBL_MIN      2.2250738585072014E-308  /* min decimal value of a "double"*/
FCHR_MAX     1048576                  /* historical default file size limit in bytes */
FLT_DIG      6                        /* digits of precision of a "float" */
FLT_MAX      3.40282347e+38F          /* max decimal value of a "float" */
FLT_MIN      1.17549435E-38F          /* min decimal value of a "float" */
INT_MAX      2147483647               /* max value of an "int" */
INT_MIN      (-2147483647-1)          /* min value of an "int" */
LINK_MAX     1000                     /* max # of links to a single file */
LOGNAME_MAX  8                        /* max # of characters in a login name */
LONG_BIT     32                       /* # of bits in a "long" */
LONG_MAX     2147483647               /* max value of a "long int" */
LONG_MIN     (-2147483647-1)          /* min value of a "long int" */
MAX_CANON    256                      /* max bytes in a line for canonical
                                      processing */
MAX_INPUT    512                      /* max size of a char input buffer */
MB_LEN_MAX   5                        /* max # of bytes in a multibyte
                                      character */
NAME_MAX     14                       /* max # of characters in a file name */
NGROUPS_MAX  16                       /* max # of groups for a user */
NL_ARGMAX    9                        /* max value of "digit" in calls to the
                                      NLS printf() and scanf() */
NL_LANGMAX   14                       /* max # of bytes in a LANG name */
NL_MSGMAX    32767                    /* max message number */
NL_NMAX      1                        /* max # of bytes in N-to-1 mapping
                                      characters */
NL_SETMAX    255                      /* max set number */
NL_TEXTMAX   255                      /* max # of bytes in a message string */
NZERO        20                       /* default process priority */
OPEN_MAX     20                       /* max # of files a process can have
                                      open */
PASS_MAX     8                        /* max # of characters in a password */
PATH_MAX     1024                     /* max # of characters in a path name */
PID_MAX      30000                    /* max value for a process ID */
PIPE_BUF     5120                     /* max # bytes atomic in write to a pipe */
PIPE_MAX     5120                     /* max # bytes written to a pipe
                                      in a write */
SCHAR_MAX    127                      /* max value of a "signed char" */
SCHAR_MIN    (-128)                   /* min value of a "signed char" */
SHRT_MAX     32767                    /* max value of a "short int" */
SHRT_MIN     (-32768)                 /* min value of a "short int" */
STD_BLK      1024                     /* # bytes in a physical I/O block */
SYS_NMLN     257                      /* 4.0 size of utsname elements */
                                      /* also defined in sys/utsname.h */
SYSPID_MAX   1                        /* max pid of system processes */
TMP_MAX      17576                    /* max # of unique names generated
                                      by tmpnam */
UCHAR_MAX    255                      /* max value of an "unsigned char" */
UID_MAX      60000                    /* max value for a user or group ID */
UINT_MAX     4294967295               /* max value of an "unsigned int" */
ULONG_MAX    4294967295               /* max value of an "unsigned long int" */
USHRT_MAX    65535                    /* max value of an "unsigned short int" */
USI_MAX      4294967295               /* max decimal value of an "unsigned" */
WORD_BIT     32                       /* # of bits in a "word" or "int" */

The following POSIX definitions are the most restrictive values to be used by a POSIX conformance application. Conforming implementations shall provide values at least this large.

_POSIX_ARG_MAX      4096  /* max length of arguments to exec */
_POSIX_CHILD_MAX    6     /* max # of processes per user ID */
_POSIX_LINK_MAX     8     /* max # of links to a single file */
_POSIX_MAX_CANON    255   /* max # of bytes in a line of input */
_POSIX_MAX_INPUT    255   /* max # of bytes in terminal
                          input queue */
_POSIX_NAME_MAX     14    /* # of bytes in a filename */
_POSIX_NGROUPS_MAX   0    /* max # of groups in a process */
_POSIX_OPEN_MAX     16    /* max # of files a process can have open */
_POSIX_PATH_MAX     255   /* max # of characters in a pathname */
_POSIX_PIPE_BUF     512   /* max # of bytes atomic in write
                          to a pipe */


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Created by unroff & hp-tools. © by Hans-Peter Bischof. All Rights Reserved (1997).

Last modified 21/April/97