System Calls                                            access(2)



NAME
     access - determine accessibility of a file

SYNOPSIS
     #include 

     int access(const char *path, int amode);


DESCRIPTION
     The access() function checks the file named by the  pathname
     pointed  to by the path argument for accessibility according
     to the bit pattern contained in amode, using the  real  user
     ID  in  place of the effective user ID and the real group ID
     in place of the effective group ID.  This  allows  a  setuid
     process  to  verify  that the user running it would have had
     permission to access this file.


     The value of amode is either the bitwise inclusive OR of the
     access  permissions  to be checked (ROK, WOK, XOK) or the
     existence test, FOK.


     These constants are defined in  as follows:

     ROK    Test for read permission.


     WOK    Test for write permission.


     XOK    Test for execute or search permission.


     FOK    Check existence of file



     See Intro(2) for additional information about  "File  Access
     Permission".


     If any access permissions are to be checked,  each  will  be
     checked  individually, as described in Intro(2). If the pro-
     cess has appropriate privileges, an implementation may indi-
     cate  success for XOK even if none of the execute file per-
     mission bits are set.

RETURN VALUES
     If the requested access is permitted, access() succeeds  and
     returns  0.  Otherwise,  -1  is returned and errno is set to



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System Calls                                            access(2)



     indicate the error.

ERORS
     The access() function will fail if:

     EACES          Permission bits of the file mode do not per-
                     mit  the requested access, or search permis-
                     sion is denied on a component  of  the  path
                     prefix.


     EFAULT          path points to an illegal address.


     EINTR           A signal  was  caught  during  the  access()
                     function.


     ELOP           Too many symbolic links were encountered  in
                     resolving path.


     ELOP           A loop exists in symbolic links  encountered
                     during resolution of the path argument.


     ENAMETOLONG    The length  of  the  path  argument  exceeds
                     {PATHMAX},   or  a  pathname  component  is
                     longer than {NAMEMAX} while POSIXNOTRUNC
                     is in effect.


     ENOENT          A component of path does not name an  exist-
                     ing file or path is an empty string.


     ENOLINK         path points to a remote machine and the link
                     to that machine is no longer active.


     ENOTDIR         A component of the  path  prefix  is  not  a
                     directory.


     ENXIO           The path argument points to a  character  or
                     block    device   special   file   and   the
                     corresponding device has been retired by the
                     fault management framework.


     EROFS           Write access is requested for a  file  on  a
                     read-only file system.



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System Calls                                            access(2)



     The access() function may fail if:

     EINVAL          The value of the amode argument is invalid.


     ENAMETOLONG    Pathname resolution of a symbolic link  pro-
                     duced  an  intermediate  result whose length
                     exceeds {PATHMAX}.


     ETXTBSY         Write access is requested for  a  pure  pro-
                     cedure (shared text) file that is being exe-
                     cuted.


USAGE
     Additional values of amode other than the set defined in the
     description  might  be  valid,  for example, if a system has
     extended access controls.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Committed                   
    
     MT-Level                     Async-Signal-Safe           
    
     Standard                     See standards(5).           
    


SEE ALSO
     Intro(2), chmod(2), stat(2), attributes(5), standards(5)
















SunOS 5.11           Last change: 8 Jul 2007                    3