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access(2)
NAME
  access - Determines the accessibility of a file

SYNOPSIS
  #include <unistd.h>

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

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  access(): XSH4.0, XSH4.2, XSH5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  path
      Points to the file pathname. When the path parameter refers to a
      symbolic link, the access() function returns information about the file
      pointed to by the symbolic link.

      Permission to access all components of the path parameter is determined
      by using a real user ID instead of an effective user ID, and a group
      access list (including a real group ID) instead of an effective group
      ID.

  access_mode
      Specifies the type of access. The bit pattern contained in the
      access_mode parameter is constructed by a logical OR of the following
      values:

      R_OK    Checks read permission.

      W_OK    Checks write permission.

      X_OK    Checks execute (search) permission.

      F_OK    Checks to see if the file exists.

DESCRIPTION
  The access() function checks for accessibility of the file specified by a
  pathname.

  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's access bits may indicate that it is
  executable, but the execve() function can fail if the file does not contain
  the proper format.

NOTES
  The access() function is supported for multi-threaded applications.

RETURN VALUES
  Upon successful completion, the access() function returns value of 0
  (zero). Otherwise, a value of -1 is returned and errno is set to indicate
  the error.

ERRORS
  If the access() function fails, access to the file specified by the path
  parameter is denied and errno may be set to one of the following values:

  [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 ``user''
      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]
      The path parameter points outside the allocated address space of the
      process.

  [EINVAL]
      [Tru64 UNIX]  The pathname contains a character with the high-order bit
      set.

  [EIO]
      [Tru64 UNIX]  An I/O error occurred while reading from or writing to
      the file system.

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

  [ENAMETOOLONG]
      A component of a pathname exceeded PATH_MAX characters, or an entire
      pathname exceeded NAME_MAX characters.

  [ENOENT]
      The named file does not exist or is an empty string.

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

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

SEE ALSO
  Functions: chmod(2), stat(2) eaccess(3)

  Standards: standards(5)

Index for Section 2

Alphabetical listing for A

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