limits(4)

limits -- header file for implementation-specific constants

Synopsis

   #include <limits.h>

Description

The header file limits.h is a list of minimal magnitude limitations imposed by a specific implementation of the operating system. The values listed below are subject to change.

ARG_MAX 10240 max length of arguments to exec

CHAR_BIT 8 max # of bits in a "char"

CHAR_MAX 127 max value of a "char"

CHAR_MIN -128 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"

FLT_DIG 6 digits of precision of a "float"

FLT_MAX 3.40282347e+38F max decimal value of a "float"

INT_MAX 0x7fffffff max value of an "int"

INT_MIN (-INT_MAX-1) min value of an "int"

LINK_MAX 1000 max # of links to a single file

LLONG_MAX 0x7fffffffffffffff max value of a "signed long long"

LLONG_MIN (-LLONG_MAX-1) min value of a "signed long long"

LOGNAME_MAX 8 max # of characters in a login name

LONG_BIT 32 # of bits in a "long"

LONG_MAX 0x7fffffffffffffff max value of a "long int"

LONG_MIN (-LONG_MAX-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 4096 max # of bytes in a message string

NZERO 20 default process priority

OPEN_MAX 60 max # of files a process can have open

PASS_MAX 80 max # of characters in a password

BC_BASE_MAX 99 max obase values bc utility allows

BC_SCALE_MAX 99 max scale value bc utility allows

BC_DIM_MAX 2048 max # of elements allowed in a bc utility array

BC_STRING_MAX 1000 max length of a bc utility string constant

COLL_WEIGHTS_MAX 2 max # weights assignable to an entry of LC_COLLATE

EXPR_NEST_MAX 32 max # of expressions allowed to be nested within parentheses by the expr utility

LINE_MAX 2048 max byte length of the utility's input line when the utility is processing text files

RE_DUP_MAX 255 max # repeated occurrences of a regexp permitted when using m,n

CHARCLASS_NAME_MAX 100 max # bytes character class name can have

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

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"

SSIZE_MAX INT_MAX max value of an "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 60002 max value for a user or group ID

UINT_MAX 0xffffffff max value of an "unsigned int"

ULLONG_MAX 0xffffffffffffffff max value of an "unsigned long long"

ULONG_MAX 0xffffffffffffffff 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 conformant 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

_POSIX_SSIZE_MAX 32767 min value stored in object of type ssize_t

_POSIX_STREAM_MAX 8 min number of streams (stdio) that one process can have open at a time

_POSIX_TZNAME_MAX 3 max number of bytes supported for name of a timezone (not the TZ variable)

ARG_MAX	10240	max length of arguments to exec
CHAR_BIT	8	max # of bits in a "char"
CHAR_MAX	127	max value of a "char"
CHAR_MIN	-128	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"
FLT_DIG	6	digits of precision of a "float"
FLT_MAX	3.40282347e+38F	max decimal value of a "float"
INT_MAX	0x7fffffff	max value of an "int"
INT_MIN	(-INT_MAX-1)	min value of an "int"
LINK_MAX	1000	max # of links to a single file
LLONG_MAX	0x7fffffffffffffff	max value of a "signed long long"
LLONG_MIN	(-LLONG_MAX-1)	min value of a "signed long long"
LOGNAME_MAX	8	max # of characters in a login name
LONG_BIT	32	# of bits in a "long"
LONG_MAX	0x7fffffffffffffff	max value of a "long int"
LONG_MIN	(-LONG_MAX-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	4096	max # of bytes in a message string
NZERO	20	default process priority
OPEN_MAX	60	max # of files a process can have open
PASS_MAX	80	max # of characters in a password
BC_BASE_MAX	99	max obase values bc utility allows
BC_SCALE_MAX	99	max scale value bc utility allows
BC_DIM_MAX	2048	max # of elements allowed in a bc utility array
BC_STRING_MAX	1000	max length of a bc utility string constant
COLL_WEIGHTS_MAX	2	max # weights assignable to an entry of LC_COLLATE
EXPR_NEST_MAX	32	max # of expressions allowed to be nested within parentheses by the expr utility
LINE_MAX	2048	max byte length of the utility's input line when the utility is processing text files
RE_DUP_MAX	255	max # repeated occurrences of a regexp permitted when using m,n
CHARCLASS_NAME_MAX	100	max # bytes character class name can have
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
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"
SSIZE_MAX	INT_MAX	max value of an "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	60002	max value for a user or group ID
UINT_MAX	0xffffffff	max value of an "unsigned int"
ULLONG_MAX	0xffffffffffffffff	max value of an "unsigned long long"
ULONG_MAX	0xffffffffffffffff	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"

_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
_POSIX_SSIZE_MAX	32767	min value stored in object of type ssize_t
_POSIX_STREAM_MAX	8	min number of streams (stdio) that one process can have open at a time
_POSIX_TZNAME_MAX	3	max number of bytes supported for name of a timezone (not the TZ variable)