isatty (2) --- test if a file is connected to a terminal  09/10/82


            _C_a_l_l_i_n_g _I_n_f_o_r_m_a_t_i_o_n

                 integer function isatty (fd)
                 file_des fd

                 Library:  vswtlb (standard Subsystem library)


            _F_u_n_c_t_i_o_n

                 'Isatty'  returns  YES  if  the  file referenced by the file
                 descriptor in 'fd' is connected to a terminal; otherwise  it
                 returns NO.  All file descriptors, including standard ports,
                 can be tested.


            _I_m_p_l_e_m_e_n_t_a_t_i_o_n

                 'Isatty'  simply  looks  in the Subsystem common area at the
                 device type in the file descriptor and  returns  YES  or  NO
                 accordingly.


            _C_a_l_l_s

                 mapsu


            _S_e_e _A_l_s_o

                 isadsk (2), isnull (2)



























            isatty (2)                    - 1 -                    isatty (2)