UNISTD(4-SVR4)      RISC/os Reference Manual       UNISTD(4-SVR4)



NAME
     unistd - header file for symbolic constants

SYNOPSIS
     #include <unistd.h>

DESCRIPTION
     The <unistd.h> header file 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
     function [see access(2)]:
        ROK   Test for read permission
        WOK   Test for write permission
        XOK   Test for execute (search) permission
        FOK   Test for existence of file

     The constants FOK, ROK, WOK and XOK and the expressions
     ROK|WOK, ROK|XOK and ROK|WOK|XOK all have distinct
     values.

     The following symbolic value is defined:
        NULL   null pointer

     The following symbolic constants are defined for the lockf
     function [see lockf(3C)]:
        FULOCK   Unlock a previously locked region
        FLOCK    Lock a region for exclusive use
        FTLOCK   Test and lock a region for exclusive use
        FTEST    Test a region for other processes locks

     The following symbolic constants are defined for the lseek
     [see lseek(2)] and fcntl [see fcntl(2)] functions (they have
     distinct values):
        SEEKSET   Set file offset to offset
        SEEKCUR   Set file offset to current plus offset
        SEEKEND   Set file offset to EOF plus offset

     The following symbolic constants are defined (with fixed
     values):
        POSIXVERSION   Integer value indicating version
                         of the POSIX standard
        XOPENVERSION   integer value indicating version of the XPG
                         to which system is compliant









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     The following symbolic constants are defined to indicate
     that the option is present:
        POSIXJOBCONTROL   implementation sup-
                             ports job control
        POSIXSAVEDIDS     the exec functions
                             [see exec(2)] save the
                             effective user and
                             group
        POSIXVDISABLE      terminal special char-
                             acters defined in
                             <termios.h> [see ter-
                             mio(7)] can be dis-
                             abled using this char-
                             acter

     The following symbolic constants are defined for sysconf
     [see sysconf(3C)]:
          SCARGMAX
          SCCHILDMAX
          SCCLKTCK
          SCJOBCONTROL
          SCNGROUPSMAX
          SCOPENMAX
          SCPAGESIZE
          SCPASSMAX
          SCSAVEDIDS
          SCVERSION
          SCXOPENVERSION

     The following symbolic constants are defined for pathconf
     [see fpathconf(3C)]:
          PCCHOWNRESTRICTED
          PCLINKMAX
          PCMAXCANON
          PCMAXINPUT
          PCNAMEMAX
          PCNOTRUNC
          PCPATHMAX
          PCPIPEBUF
          PCVDISABLE

     The following symbolic constants are defined for file
     streams:

          STDINFILENO        File number of stdin.  It is 0.

          STDOUTFILENO       File number of stout.  It is 1.

          STDERRFILENO       File number of stderr.  It is 2.

     The following pathnames are defined:




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          GFPATH             Pathname of the group file.

          PFPATH             Pathname of the passwd file.

NOTES
     The following values for constants are defined for this
     release of the system:

          POSIXVERSION      198808L

          XOPENVERSION      3

SEE ALSO
     access(2), exec(2), fcntl(2), lseek(2), termios(2),
     fpathconf(3C), sysconf(3C), group(4), passwd(4).
     termio(7) in the System Administrator's Reference Manual.







































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