NAME

unistd − header for symbolic constants

SYNOPSIS

#include <unistd.h>

DESCRIPTION

The <unistd.h> header defines the symbolic constants and structures which are not already defined or declared in some other header. The contents of this header are shown below. 

The following symbolic constants are defined 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. 

The following constant is declared:

NULL Null pointer

The following symbolic constants are defined for the lockf(3C) function:

F_ULOCK Unlock a previously locked region. 

F_LOCK Lock a region for exclusive use. 

F_TLOCK Test and lock a region for exclusive use. 

F_TEST Test a region for other processes locks. 

The following symbolic constants are defined for the lseek(2) and fcntl(2) functions (they 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. 

The following symbolic constants are defined (with fixed values):

_POSIX_VERSION Integer value indicating version of the POSIX standard (see standards(5). 

_XOPEN_VERSION integer value indicating version of the XPG to which system conforms. 

The following symbolic constants are defined to indicate that the option is present:

_POSIX_JOB_CONTROL
Implementation supports job control.

_POSIX_SAVED_IDS The exec functions (see exec(2)) save the effective user and group. 

_POSIX_VDISABLE Terminal special characters defined in <termios.h> (see termio(7I)) can be disabled using this character. 

The following symbolic constants are defined for sysconf(3C)):

_SC_ARG_MAX
_SC_CLK_TCK
_SC_JOB_CONTROL
_SC_NGROUPS_MAX
_SC_OPEN_MAX
_SC_PAGESIZE
_SC_PASS_MAX
_SC_SAVED_IDS
_SC_VERSION
_SC_XOPEN_VERSION

The following symbolic constants are defined for fpathconf(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

The following symbolic constants are defined for file streams:

STDIN_FILENO File number (0) of stdin. 

STDOUT_FILENO File number (1) of stout. 

STDERR_FILENO File number (2) of stderr. 

The following pathnames are defined:

GF_PATH Pathname of the group file. 

PF_PATH Pathname of the passwd file. 

The following values for constants are defined:

_POSIX_VERSION 199009L

_XOPEN_VERSION 3

SEE ALSO

access(2), exec(2), fcntl(2), fpathconf(2), lseek(2), lockf(3C), sysconf(3C), termios(3), group(4), passwd(4), standards(5), termio(7I)

SunOS 5.6  —  Last change: 21 Mar 1997