UNISTD(5)
NAME
unistd.h − standard structures and symbolic constants
SYNOPSIS
#include <unistd.h>
DESCRIPTION
The header <unistd.h> defines the following structures and symbolic constants:
Symbolic constants for the access(2) function:
R_OK Test for read permission
W_OK Test for write permission
X_OK Test for execute (search) permission
F_OK Test for existence of file
The constants F_OK, R_OK, W_OK , and X_OK and the expressions R_OK|W_OK, R_OK|X_OK, and R_OK|W_OK|X_OK all have distinct values.
Symbolic constant representing a null pointer:
NULL
Symbolic constants for the lseek(2) and fcntl(2) functions (the following constants have distinct values):
SEEK_SET Set file offset to "offset"
SEEK_CUR Set file offset to current plus "offset"
SEEK_END Set file offset to EOF plus "offset"
Symbolic constants (with fixed values):
_POSIX_VERSION Integer value indicating version of IEEE Std 1003.1 standard implemented. The current value is 198808L, indicating the (4-digit) year and (2-digit) month that the standard was approved by the IEEE Standards Board.
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 determined at execution time through sysconf(2) or pathconf(2):
_POSIX_CHOWN_RESTRICTED the use of chown(2) is restricted to a process with appropriate privileges
_POSIX_JOB_CONTROL implementation supports job control (true of all HP-UX implementations)
_POSIX_NO_TRUNC pathname components longer than NAME_MAX generate an error
_POSIX_SAVED_IDS effective user and group are saved across an exec(2) call (true of all HP-UX implementations)
_POSIX_VDISABLE terminal special characters can be disabled using this character (see termio(7)).
Symbolic constants for sysconf(2):
_SC_ARG_MAX
_SC_CHILD_MAX
_SC_CLK_TCK
_SC_JOB_CONTROL
_SC_NGROUPS_MAX
_SC_OPEN_MAX
_SC_PASS_MAX
_SC_SAVED_IDS
_SC_VERSION
_SC_XOPEN_VERSION
Symbolic constants for pathconf(2):
_PC_CHOWN_RESTRICTED
_PC_LINK_MAX
_PC_MAX_CANON
_PC_MAX_INPUT
_PC_NAME_MAX
_PC_NO_TRUNC
_PC_PATH_MAX
_PC_PIPE_BUF
_PC_VDISABLE
Symbolic constants for file streams:
STDIN_FILENO File number of stdin.
STDOUT_FILENO File number of stdout.
STDERR_FILENO File number of stderr.
The following are declared as either functions or macros:
| _exit() | execlp() | getpgrp() | setgid() |
| access() | execv() | getpid() | setpgid() |
| alarm() | execve() | getppid() | setsid() |
| chdir() | execvp() | getuid() | setuid() |
| chown() | fork() | isatty() | sleep() |
| close() | fpathconf() | link() | sysconf() |
| ctermid() | getcwd() | lseek() | tcgetpgrp() |
| cuserid() | getegid() | pathconf() | tcsetpgrp() |
| dup() | geteuid() | pause() | ttyname() |
| dup2() | getgid() | pipe() | unlink() |
| execl() | getgroups() | read() | write() |
| execle() | getlogin() | rmdir() |
SEE ALSO
access(2), chown(2), exit(2), fcntl(2), kill(2), lseek(2), open(2), pathconf(2), sysconf(2), limits(5), termio(7).
AUTHOR
Unistd was developed by Hewlett-Packard Company.
STANDARDS CONFORMANCE
unistd.h: XPG2, XPG3, POSIX.1, FIPS 151-1
Hewlett-Packard Company — HP-UX Release 7.0: Sept 1989