limits(4) limits(4)
NAME
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.
ARG_MAX 5120 /* 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 100 /* 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 /* max size of a file 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 1024 /* 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 255 /* max bytes in a line for canonical
processing */
MAX_INPUT 25255 * 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 25 /* max # of files a process can have
open */
PASS_MAX 8 /* max # of characters in a password */
PATH_MAX 255 /* 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 */
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limits(4) limits(4)
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 */
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 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 */
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