4.4BSD/usr/share/man/cat2/access.0

ACCESS(2)                   BSD Programmer's Manual                  ACCESS(2)

NNAAMMEE
     aacccceessss - check access permissions of a file or pathname

SSYYNNOOPPSSIISS
     ##iinncclluuddee <<uunniissttdd..hh>>

     _i_n_t
     aacccceessss(_c_o_n_s_t _c_h_a_r _*_p_a_t_h, _i_n_t _m_o_d_e);

DDEESSCCRRIIPPTTIIOONN
     The aacccceessss() function checks the accessibility of the file named by _p_a_t_h
     for the access permissions indicated by _m_o_d_e. The value of _m_o_d_e is the
     bitwise inclusive OR of the access permissions to be checked (R_OK for
     read permission, W_OK for write permission and X_OK for execute/search
     permission) or the existence test, F_OK. All components of the pathname
     _p_a_t_h are checked for access permissions (including F_OK).

     The real user ID is used in place of the effective user ID and the real
     group access list (including the real group ID) are used in place of the
     effective ID for verifying permission.

     Even if a process has appropriate privileges and indicates success for
     X_OK, the file may not actually have execute permission bits set.  Like-
     wise for R_OK and W_OK.

RREETTUURRNN VVAALLUUEESS
     If _p_a_t_h cannot be found or if any of the desired access modes would not
     be granted, then a -1 value is returned; otherwise a 0 value is returned.

EERRRROORRSS
     Access to the file is denied if:

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

     [EINVAL]      The pathname contains a character with the high-order bit
                   set.

     [ENAMETOOLONG]
                   A component of a pathname exceeded 255 characters, or an
                   entire path name exceeded 1023 characters.

     [ENOENT]      The named file does not exist.

     [EACCES]      Search permission is denied for a component of the path
                   prefix.

     [ELOOP]       Too many symbolic links were encountered in translating the
                   pathname.

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

     [ETXTBSY]     Write access is requested for a pure procedure (shared
                   text) file presently being executed.

     [EACCES]      Permission bits of the file mode do not permit the request-
                   ed access, or search permission is denied on a component of
                   the path prefix.  The owner of a file has permission
                   checked with respect to the ``owner'' read, write, and exe-
                   cute mode bits, members of the file's group other than the
                   owner have permission checked with respect to the ``group''
                   mode bits, and all others have permissions checked with re-

                   spect to the ``other'' mode bits.

     [EFAULT]      _P_a_t_h points outside the process's allocated address space.

     [EIO]         An I/O error occurred while reading from or writing to the
                   file system.

SSEEEE AALLSSOO
     chmod(2),  stat(2)

SSTTAANNDDAARRDDSS
     AAcccceessss() conforms to IEEE Std 1003.1-1988 (``POSIX'').

CCAAVVEEAATT
     AAcccceessss() is a potential security hole and should never be used.

4th Berkeley Distribution        June 4, 1993                                2