Function: file-locked-p

file-locked-p is a function defined in filelock.c.

Signature

(file-locked-p FILENAME)

Documentation

Return a value indicating whether FILENAME is locked.

The value is nil if the FILENAME is not locked, t if it is locked by you, else a string saying which user has locked it.

Other relevant functions are documented in the file group.

View in manual

Probably introduced at or before Emacs version 18.

Shortdoc

;; file
(file-locked-p "/tmp/foo")
    e.g. => nil

Source Code

// Defined in /usr/src/emacs/src/filelock.c
{
#ifdef MSDOS
  return Qnil;
#else
  Lisp_Object ret;
  int owner;
  lock_info_type locker;

  /* If the file name has special constructs in it,
     call the corresponding file name handler.  */
  Lisp_Object handler;
  handler = Ffind_file_name_handler (filename, Qfile_locked_p);
  if (!NILP (handler))
    {
      return calln (handler, Qfile_locked_p, filename);
    }

  Lisp_Object lfname = make_lock_file_name (filename);
  if (NILP (lfname))
    return Qnil;

  owner = current_lock_owner (&locker, lfname);
  switch (owner)
    {
    case I_OWN_IT: ret = Qt; break;
    case ANOTHER_OWNS_IT:
      ret = make_string (locker.user, locker.at - locker.user);
      break;
    case  0: ret = Qnil; break;
    default: report_file_errno ("Testing file lock", filename, owner);
    }

  return ret;
#endif
}