n                  Upon successful completion, the count of bytes
                       placed in the user_buffer
    -1                 Indicates an error. The buffer is unchanged,
                       and errno is set to indicate the error:

                       o  EACCES - Read permission is denied in the
                          directory where the symbolic link is being
                          read, or search permission is denied for a
                          component of the path prefix of link_name.

                       o  ENAMETOOLONG - The length of the link_name
                          argument exceeds PATH_MAX, or a pathname
                          component is longer than NAME_MAX.

                       o  Any errno value from close, open, or read.