#include <limits.h>
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) |