unistd(5)unistd(5)NAME
unistd: unistd.h - standard structures and symbolic constants
SYNOPSISDESCRIPTION
The header defines the following structures and symbolic constants:
Symbolic constants for the function:
Test for read permission.
Test for write permission.
Test for execute (search) permission.
Test for existence of file.
The constants and and the expressions and all have distinct values.
Symbolic constant representing a null pointer:
Symbolic constants for the and functions (the following constants have
distinct values):
Set file offset to "offset".
Set file offset to current plus "offset".
Set file offset to EOF plus "offset".
Symbolic constants (with fixed values):
Integer value indicating version of
IEEE Std 1003.1 standard implemented.
The current value is 199009L, indicat‐
ing the (4-digit) year and (2-digit)
month that the standard was approved by
the IEEE Standards Board. However, if
any of the symbols or is defined before
is included, the value of this symbol
will be 198808L.
Integer value indicating version of
IEEE Std1003.2 standard implemented.
The current value is 199209L, indicat‐
ing the (4-digit) year and (2-digit)
month that the standard was approved by
the IEEE Standards Board.
Integer value indicating version of
IEEE Std 1003.2 C-Language Binding
Option implemented. The current value
is 199209L, indicating the (4-digit)
year and (2-digit) month that the stan‐
dard was approved by the IEEE Standards
Board.
Integer value indicating issue number of the
X/Open Portability Guide implemented.
The current value is 4, indicating
Issue 4. However, if the symbol is
defined before is included, the value
of this symbol will be 3.
The following symbolic constants are defined in this header if the
state of the corresponding option or restriction does not vary after
compilation. If a symbol is absent from this header, the value or
presence of the corresponding option or restriction should be deter‐
mined at execution time through or
The use of is restricted to processes that have
appropriate privileges.
Implementation supports job control (true of all
HP-UX implementations).
Pathname components longer than
generate an error.
Implementation supports Realtime Signals Extensions
(true of all HP-UX implementations).
Effective user and group are saved across an
call (true of all HP-UX implementa‐
tions).
Implementation supports File Synchronization (true of all
HP-UX implementations). See open(2).
Implementation supports Synchronized IO (true of all
HP-UX implementations). See open(2).
Terminal special characters can be disabled using this character
(see
termio(7)).
Implementation supports POSIX threads.
All POSIX.2 C-language functionality is provided
in the default libraries used by the C
compiler (see cc(1)).
New locales can be defined by using the
command (see localedef(1M)).
The system supports IEEE Std1003.2a (POSIX User Portability
Utilities Option).
At least one terminal exists that supports all required POSIX.2a
commands.
All symbolic constants whose names begin and (see confstr(3C), path‐
conf(2), and sysconf(2)) are defined.
The following symbolic constants for file streams are defined:
File number of standard input
(stdin).
File number of standard output
(stdout).
File number of standard error
(stderr).
The types and are defined.
Declarations are provided for the following functions:
access()alarm()brk()chdir()chown()chroot()close()confstr()crypt()ctermid()cuserid()dup()dup2()encrypt()endusershell()execl()execle()execlp()execv()execve()execvp()_exit()fchown()fork()fpathconf()fsync()ftruncate()getcwd()getegid()geteuid()getgid()getgroups()gethostname()getlogin()getopt()getpass()getpgrp()getpgrp2()getpid()getppid()getuid()getusershell()initgroups()ioctl()isatty()link()lockf()logname()lseek()mkstemp()mktemp()nice()pathconf()pause()pipe()prealloc()read()readlink()rmdir()sbrk()setgid()setgroups()sethostname()setpgid()setpgrp()setpgrp2()setresgid()setresuid()setsid()setuid()setusershell()sgetl()sleep()sputl()swab()swapon()symlink()sync()sysconf()tcgetpgrp()tcsetpgrp()truncate()ttyname()ttyslot()unlink()vfork()write()AUTHOR
was developed by HP.
SEE ALSOaccess(2), chown(2), exit(2), fcntl(2), kill(2), lseek(2), open(2),
pathconf(2), sysconf(2), confstr(3C), limits(5), stdsyms(5), termio(7).
STANDARDS CONFORMANCEunistd(5)
