HPUX limits[5]
limits(5) limits(5)
NAME
limits - implementation-specific constants
SYNOPSIS
#include <limits.h>
DESCRIPTION
The following symbols are defined in <limits.h> 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 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 only if the preprocessor
macro _XPG2 is defined, either by the compilation flag
-D_XPG2, or by a #define directive in the source before
<limits.h> 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
determined 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 X/Open
Portability Guide, Issue 2, and for backward compatibility with
earlier versions of HP-UX. The _XPG2 flag should not be defined in
new applications.
By including the <limits.h> 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.
lB lBw(2.6i) rB lb p-2 l rB.
Constant Description HP-UX Value
Hewlett-Packard Company - 1 - HP-UX Release 9.0: August 1992
limits(5) limits(5)
ARG_MAX T{ Max length of arguments to exec(2) in bytes, including
environment data T} 5120 +* CHAR_BIT T{ Number of bits in a char
T} 8 = CHAR_MAX T{ Max integer value of a char T} 127 =
CHAR_MIN T{ Min integer value of a char T} -128 = CHILD_MAX T{ Max
number of simultaneous processes per user ID T} 25 +-* CLK_TCK T{
Number of clock ticks per second T} 50 +# DBL_DIG T{ Digits of
precision of a double T} 16 + DBL_MAX T{ Max positive value of a
double T} 1.7976931348623157e+308 + DBL_MIN T{ Min positive value
of a double T} 4.94065645841246544e-324 - FCHR_MAX T{ Max file
offset in bytes T} INT_MAX +-* FLT_DIG T{ Digits of precision of a
float T} 6 + FLT_MAX T{ Max positive value of a float
T} 3.40282346638528860e+38 + FLT_MIN T{ Min positive value of a
float T} 1.40129846432481707e-45 - INT_MAX T{ Max decimal value of
an int T} 2147483647 + INT_MIN T{ Min decimal value of an int
T} -2147483648 - LINE_MAX T{ Max number of characters in a single
line T} 2048 = LINK_MAX T{ Max number of links to a single file
T} 32767 +* LOCK_MAX T{ Max number of entries in system lock table
T} 32 +-* LONG_BIT T{ Number of bits in a long T} 32 +
LONG_MAX T{ Max decimal value of a long T} 2147483647 +
LONG_MIN T{ Min decimal value of a long T} -2147483648 -
MAX_CANON T{ Max number of bytes in terminal canonincal input line
T} 512 +* MAX_CHAR T{ Max number of bytes in terminal input queue
T} MAX_INPUT =* MAX_INPUT T{ Max number of bytes in terminal input
queue T} 512 +* NAME_MAX T{ Max number of bytes in a path name
component T} 14 +* NL_ARGMAX T{ Max value of "digits" in calls to
the NLS printf(3S) and scanf(3S) functions T} 9 = NL_MSGMAX T{ Max
message number in an NLS message catalog T} 32767 + NL_SETMAX T{ Max
set number in an NLS message catalog T} 255 + NL_TEXTMAX T{ Max
number of bytes in an NLS message string T} 8192 + NGROUPS_MAX T{
Max number of supplementary groups per process T} 20 + OPEN_MAX T{
Max number of files a process can have open T} 60 +* PASS_MAX T{
Max number of chars in a password T} 8 + PATH_MAX T{ Max number of
characters in a path name excluding the null terminator T} 1023 +*
PID_MAX T{ Max value for a process ID T} 30000 + PIPE_BUF T{ Max
number of bytes atomic in write to a pipe T} 8192 +* PIPE_MAX T{
Max number of bytes writable to a pipe in one write T} INT_MAX +
PROC_MAX T{ Max number of simultaneous processes on system T} 84
+-* SCHAR_MAX T{ Max integer value of a signed char T} 127 =
SCHAR_MIN T{ Min integer value of a signed char T} -128 =
SHRT_MAX T{ Max decimal value of a short T} 32767 + SHRT_MIN T{
Min decimal value of a short T} -32768 - STD_BLK T{ Number of
bytes in a physical I/O block T} 512 + SYSPID_MAX T{ Max process
ID of system processes T} 4 +-* SYS_NMLN T{ Length of strings
returned by uname(2) T} 8 +* SYS_OPEN T{ Max number of files open
on system T} 120 +-* TMP_MAX T{ Max number of unique names
generated by tmpnam(3S) T} 17576 + UCHAR_MAX T{ Max integer value of
an unsigned char T} 255 = UID_MAX T{ Smallest unattainable value
for a user or group ID T} 60000 + UINT_MAX T{ Max decimal value of
an unsigned int T} 4294967295 + ULONG_MAX T{ Max decimal value of an
unsigned long T} 4294967295 + USHRT_MAX T{ Max decimal value of an
unsigned short T} 65535 + USI_MAX T{ Max decimal value of an
Hewlett-Packard Company - 2 - HP-UX Release 9.0: August 1992
limits(5) limits(5)
unsigned int T} UINT_MAX =* WORD_BIT T{ Number of bits in a "word"
(int) T} 32 +
EXAMPLES
UID_MAX has an HP-UX value of 60000 + , which means that on all HP-UX
systems the smallest unattainable value for a user or group ID is at
least 60000. A particular system might be capable of supporting more
than 60000 user or group IDs, in which case its <limits.h> file sets
UID_MAX to a higher value; however, any application assuming such a
higher value is not guaranteed to be portable to all HP-UX systems.
AUTHOR
limits was developed by HP.
SEE ALSO
exec(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).
Series 300/400 and 700
config(1M).
Series 800
uxgen(1M).
STANDARDS CONFORMANCE
<limits.h>: AES, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1, POSIX.2, ANSI
C
Hewlett-Packard Company - 3 - HP-UX Release 9.0: August 1992