limits(5)limits(5)NAMElimits - implementation-specific constants
SYNOPSISDESCRIPTION
The following symbols are defined in and are used throughout the
descriptive text of this manual. The column headed HP-UX Value lists
the values that application writers should assume for portability
across all HP-UX systems.
Symbols after values are interpreted as follows:
Actual limit might be greater than specified value on certain
HP-UX systems.
Actual limit might be greater than value specified in
on certain HP-UX systems.
Actual limit might be less than the specified value on certain
HP-UX systems.
Actual limit is always equal to the specified value
and does not vary across HP-UX systems.
The name of this limit is defined
if the preprocessor macro is defined, either by the compi‐
lation flag or by a directive in the source before is
included in the source.
The value defined for this limit might not be a compile-time
constant.
The value defined always evaluates to an integer expression
at run time.
Some of these limits vary with system configuration, and can be deter‐
mined dynamically by using sysconf(2). Others can vary according to
file system or device associated with a specific file, and can be
determined with pathconf(2). Others are obsolescent because they are
redundant with other limits or not useful in portable applications.
They are provided only for importability of applications from other
systems, to support applications that comply with the and for backward
compatibility with earlier versions of HP-UX. The flag should not be
defined in new applications.
By including the file in the compilation an application can test the
appropriate limits to determine whether it can operate on a particular
system, or it might even alter its behavior to match the system to
increase its portability across a varying range of limit settings and
systems.
Constant Description HP-UX Value
────────────────────────────────────────────────────────────────────
ARG_MAX Max length of arguments to 5120 +*
exec(2) in bytes, including
environment data
CHAR_BIT Number of bits in a 8 =
CHAR_MAX Max integer value of a 127 =
CHAR_MIN Min integer value of a -128 =
CHILD_MAX Max number of simultaneous 25 +-*
processes per user ID
CLK_TCK Number of clock ticks per 50 +#
second
DBL_DIG Digits of precision of a 15 +
DBL_MAX Max positive value of a 1.7976931348623157e+308 +
DBL_MIN Min positive value of a 4.94065645841246544e-324 -
FCHR_MAX Max file offset in bytes INT_MAX +-*
FLT_DIG Digits of precision of a 6 +
FLT_MAX Max positive value of a 3.40282346638528860e+38 +
FLT_MIN Min positive value of a 1.40129846432481707e-45 -
INT_MAX Max decimal value of an 2147483647 +
INT_MIN Min decimal value of an -2147483648 -
LINE_MAX Max number of characters in 2048 =
a single line
LINK_MAX Max number of links to a 32767 +*
single file
LOCK_MAX Max number of entries in 32 +-*
system lock table
LONG_BIT Number of bits in a 32 +
LONG_MAX Max decimal value of a 2147483647 +
LONG_MIN Min decimal value of a -2147483648 -
MAX_CANON Max number of bytes in ter‐ 512 +*
minal canonical input line
MAX_CHAR Max number of bytes in ter‐ MAX_INPUT =*
minal input queue
MAX_INPUT Max number of bytes in ter‐ 512 +*
minal input queue
NAME_MAX Max number of bytes in a 14 +*
path name component
NL_ARGMAX Max value of "digits" in 9 =
calls to the NLS printf(3S)
and scanf(3S) functions
NL_MSGMAX Max message number in an NLS 32767 +
message catalog
NL_SETMAX Max set number in an NLS 255 +
message catalog
NL_TEXTMAX Max number of bytes in an 8192 +
NLS message string
NGROUPS_MAX Max number of supplementary 20 ++
groups per process
OPEN_MAX Max number of files a 60 +*
process can have open
PASS_MAX Max number of chars in a 8 +
password
PATH_MAX Max number of characters in 1023 +*
a path name excluding the
null terminator
PID_MAX Max value for a process ID 30000 +
PIPE_BUF Max number of bytes atomic 8192 +*
in write to a pipe
PIPE_MAX Max number of bytes writable INT_MAX +
to a pipe in one write
PROC_MAX Max number of simultaneous 84 +-*
processes on system
SCHAR_MAX Max integer value of a 127 =
SCHAR_MIN Min integer value of a -128 =
SHRT_MAX Max decimal value of a 32767 +
SHRT_MIN Min decimal value of a -32768 -
STD_BLK Number of bytes in a physi‐ 512 +
cal I/O block
SYSPID_MAX Max process ID of system 4 +-*
processes
SYS_NMLN Length of strings returned 8 +*
by uname(2)
SYS_OPEN Max number of files open on 120 +-*
system
TMP_MAX Max number of unique names 17576 +
generated by tmpnam(3S)
UCHAR_MAX Max integer value of an 255 =
UID_MAX Smallest unattainable value 2147483647 +
for a user or group ID
UINT_MAX Max decimal value of an 4294967295 +
ULONG_MAX Max decimal value of an 4294967295 +
USHRT_MAX Max decimal value of an 65535 +
USI_MAX Max decimal value of an UINT_MAX =*
WORD_BIT Number of bits in a "word" 32 +
EXAMPLES
has an HP-UX value of which means that on all HP-UX systems the small‐
est unattainable value for a user or group ID is at least 2147483647.
A particular system might be capable of supporting more than 2147483647
user or group IDs, in which case its file sets to a higher value; how‐
ever, any application assuming such a higher value is not guaranteed to
be portable to all HP-UX systems.
has an HP-UX value of which means that on all HP-UX systems the small‐
est maximum number of supplementary groups per process is at least 20.
A particular system might be capable of supporting more than 20 supple‐
mentary groups per process, in which case will return a larger value
than that specified in however, any application assuming such a higher
value is not guaranteed to be portable to all HP-UX systems.
AUTHORlimits was developed by HP.
SEE ALSOexec(2), fcntl(2), fork(2), getgroups(2), link(2), lockf(2), open(2),
pathconf(2), sysconf(2), uname(2), write(2), printf(3S), scanf(3S),
tmpnam(3S), passwd(4), values(5), termio(7).
STANDARDS CONFORMANCElimits(5)
