

            getfd$ (6) --- look for an empty file descriptor         03/25/82


            _C_a_l_l_i_n_g _I_n_f_o_r_m_a_t_i_o_n

                 file_des function getfd$ (fd)
                 file_des fd

                 Library:  vswtlb (standard Subystem library)


            _F_u_n_c_t_i_o_n

                 'Getfd$'  is  used  by  'open' and 'mkfd$' to find an unused
                 file descriptor with which to set up a  file  unit.   If  it
                 could  find one, it returns that file descriptor; otherwise,
                 it returns ERR.


            _I_m_p_l_e_m_e_n_t_a_t_i_o_n

                 The file descriptor list is searched to  find  one  that  is
                 available.   The  search is attempted first on file descrip-
                 tors that lie within the current page of memory.  If one  is
                 not  found,  the  search  is then performed on any remaining
                 file descriptors (possibly requiring paging to bring in  the
                 required  data);  if  a free descriptor is found, then it is
                 returned to the caller.  If none are found this time, ERR is
                 returned.


            _A_r_g_u_m_e_n_t_s _M_o_d_i_f_i_e_d

                 fd


            _S_e_e _A_l_s_o

                 mkfd$ (6), open (2)






















            getfd$ (6)                    - 1 -                    getfd$ (6)


