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.
ARGMAX 5120 /* max length of arguments to exec */
CHARBIT 8 /* max # of bits in a "char" */
CHARMAX 255 /* max value of a "char" */
CHARMIN 0 /* min value of a "char" */
CHILDMAX 25 /* max # of processes per user id */
CLKTCK 100 /* clock ticks per second */
DBLDIG 15 /* digits of precision of a "double" */
DBLMAX 1.7976931348623157E+308 /* max decimal value of a "double"*/
DBLMIN 2.2250738585072014E-308 /* min decimal value of a "double"*/
FCHRMAX 1048576 /* max size of a file in bytes */
FLTDIG 6 /* digits of precision of a "float" */
FLTMAX 3.40282347e+38F /* max decimal value of a "float" */
FLTMIN 1.17549435E-38F /* min decimal value of a "float" */
INTMAX 2147483647 /* max value of an "int" */
INTMIN (-2147483647-1) /* min value of an "int" */
LINKMAX 1024 /* max # of links to a single file */
LOGNAMEMAX 8 /* max # of characters in a login name */
LONGBIT 32 /* # of bits in a "long" */
LONGMAX 2147483647 /* max value of a "long int" */
LONGMIN (-2147483647-1) /* min value of a "long int" */
MAXCANON 255 /* max bytes in a line for canonical
processing */
MAXINPUT 25255 * max size of a char input buffer */
MBLENMAX 5 /* max # of bytes in a multibyte
character */
NAMEMAX 14 /* max # of characters in a file name */
NGROUPSMAX 16 /* max # of groups for a user */
NLARGMAX 9 /* max value of "digit" in calls to the
NLS printf() and scanf() */
NLLANGMAX 14 /* max # of bytes in a LANG name */
NLMSGMAX 32767 /* max message number */
NLNMAX 1 /* max # of bytes in N-to-1 mapping
characters */
NLSETMAX 255 /* max set number */
NLTEXTMAX 255 /* max # of bytes in a message string */
NZERO 20 /* default process priority */
OPENMAX 25 /* max # of files a process can have
open */
PASSMAX 8 /* max # of characters in a password */
PATHMAX 255 /* max # of characters in a path name */
PIDMAX 30000 /* max value for a process ID */
PIPEBUF 5120 /* max # bytes atomic in write to a pipe */
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limits(4) limits(4)
PIPEMAX 5120 /* max # bytes written to a pipe
in a write */
SCHARMAX 127 /* max value of a "signed char" */
SCHARMIN (-128) /* min value of a "signed char" */
SHRTMAX 32767 /* max value of a "short int" */
SHRTMIN (-32768) /* min value of a "short int" */
STDBLK 1024 /* # bytes in a physical I/O block */
SYSNMLN 257 /* 4.0 size of utsname elements */
/* also defined in sys/utsname.h */
SYSPIDMAX 1 /* max pid of system processes */
UCHARMAX 255 /* max value of an "unsigned char" */
UIDMAX 60000 /* max value for a user or group ID */
UINTMAX 4294967295 /* max value of an "unsigned int" */
ULONGMAX 4294967295 /* max value of an "unsigned long int" */
USHRTMAX 65535 /* max value of an "unsigned short int" */
USIMAX 4294967295 /* max decimal value of an "unsigned" */
WORDBIT 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.
POSIXARGMAX 4096 /* max length of arguments to exec */
POSIXCHILDMAX 6 /* max # of processes per user ID */
POSIXLINKMAX 8 /* max # of links to a single file */
POSIXMAXCANON 255 /* max # of bytes in a line of input */
POSIXMAXINPUT 255 /* max # of bytes in terminal
input queue */
POSIXNAMEMAX 14 /* # of bytes in a filename */
POSIXNGROUPSMAX 0 /* max # of groups in a process */
POSIXOPENMAX 16 /* max # of files a process can have open */
POSIXPATHMAX 255 /* max # of characters in a pathname */
POSIXPIPEBUF 512 /* max # of bytes atomic in write
to a pipe */
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