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ACCESS(2)                     System Calls Manual                    ACCESS(2)

NAME
       access - determine accessibility of file

SYNOPSIS
       #include <sys/types.h>
       #include <unistd.h>

       #define R_OK    4/* test for read permission */
       #define W_OK    2/* test for write permission */
       #define X_OK    1/* test for execute (search) permission */
       #define F_OK    0/* test for presence of file */

       int access(const char *path, mode_t mode)

DESCRIPTION
       Access  checks the given file path for accessibility according to mode,
       which is an inclusive or of the bits R_OK, W_OK and  X_OK.   Specifying
       mode  as  F_OK  (i.e.,  0) tests whether the directories leading to the
       file can be searched and the file exists.

       The real user ID and the group access list (including  the  real  group
       ID) are used in verifying permission, so this call is useful to set-UID
       programs.

       Notice that only access bits are checked.  A directory may be indicated
       as  writable by access, but an attempt to open it for writing will fail
       (although files may be created there); a file may look executable,  but
       execve will fail unless it is in proper format.

RETURN VALUE
       If path 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.

ERRORS
       Access to the file is denied if one or more of the following are true:

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

       [ENAMETOOLONG] The path name exceeds PATH_MAX 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.  (Minix-vmd)

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

       [EACCES]       Permission bits of the  file  mode  do  not  permit  the
                      requested  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 execute 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 respect to the ``other'' mode
                      bits.

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

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

SEE ALSO
       chmod(2), stat(2).

4th Berkeley Distribution        May 22, 1986                        ACCESS(2)
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | SEE ALSO